A review of heat pump water heating systems
Arif Hepbasli a ,*,Yildiz Kalinci b
a Department of Mechanical Engineering,Faculty of Engineering,Ege University,35100Izmir,Turkey
b
Plumbing Technology,Department of Technical Programs,Izmir Vocational School,Dokuz Eylul University,Education Campus Buca,Izmir,Turkey
Contents 1.Introduction....................................................................................................12122.A brief description of HPWH technology .............................................................................12133.A brief historical development of heat pumps and HPWHs ..............................................................12134.
Reviewing and classifying studies conducted on HPWHs ................................................................12144.1.Reviewing studies conducted.................................................................................12144.2.Classifying studies conducted ................................................................................12245.
Modeling ......................................................................................................12265.1.General energy and exergy balance equations ...................................................................12265.2.Improvement potential .....................................................................................12265.3.Some thermodynamic parameters.............................................................................12266.
Conclusions ....................................................................................................1228Acknowledgements..............................................................................................1228References.....................................................................................................
1228
Renewable and Sustainable Energy Reviews 13(2009)1211–1229
A R T I C L E I N F O Article history:
Received 7February 2008Accepted 20August 2008
Keywords:
Heat pump water heaters
Ground-source heat pump water heaters Air-source heat pumps Solar-assisted heat pumps Exergy
Sustainable development
A B S T R A C T
A heat pump water heater (HPWH)operates on an electrically driven vapor-compression cycle and pumps energy from the air in its surroundings to water in a storage tank,thus raising the temperature of the water.HPWHs are a promising technology in both residential and commercial applications due to both improved ef?ciency and air conditioning bene?ts.
Residential HPWH units have been available for more than 20years,but have experienced limited success in the https://www.doczj.com/doc/3e11311459.html,mercial-scale HPWHs are also a very promising technology,while their present market share is extremely low.
This study dealt with reviewing HPWH systems in terms of energetic and exergetic aspects.In this context,HPWH technology along with its historical development was brie?y given ?rst.Next,a comprehensive review of studies conducted on them were classi?ed and presented in tables.HPWHs were then modeled for performance evaluation purposes by using energy and exergy analysis methods.Finally,the results obtained were discussed.It is expected that this comprehensive review will be very bene?cial to everyone involved or interested in the energetic and exergetic design,simulation,analysis,performance assessment and applications of various types of HPWH systems.
?2008Elsevier Ltd.All rights reserved.
*Corresponding author.Tel.:+902323434000x5124;fax:+902323888562.
E-mail addresses:arif.hepbasli@https://www.doczj.com/doc/3e11311459.html,.tr ,hepbasli@https://www.doczj.com/doc/3e11311459.html,.tr (A.Hepbasli),yildiz.kalinci@https://www.doczj.com/doc/3e11311459.html,.tr (Y.Kalinci).
Abbreviations:A/C,air/conditioning;ASHP,air-source heat pump;ASHPWH,air-source heat pump water heater;CACS,conventional air-conditioning system;CHP,combined heat and power;DHW,domestic hot water;DX-SAHP,direct-expansion solar-assisted heat pump;DX-SAHPWH,direct-expansion solar-assisted heat pump water heater;EF,energy factor;EHP,electric driven heat pump;EUS,energy utilization systems;GEHP,gas engine driven heat pump;GSHP,ground-source heat pump;HP,heat pump;HPSAHP,heat-pipe enhanced solar-assisted heat pump water heater;HPWH,heat pump water heater;HVAC,heating ventilating and air conditioning;ISAHP,integral type solar-assisted heat pump water heater;PV,photovoltaic;SAS-HPWH,solar-air source heat pump water heater;SF,solar fraction;WH,water heater;WLHPS,water-loop heat pump system;ZNEH,zero net energy homes.
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Renewable and Sustainable Energy Reviews
j ou r na l h o m e p a g e:w w w.el s e v i e r.co m /l o c a t e /r se r
1364-0321/$–see front matter ?2008Elsevier Ltd.All rights reserved.doi:10.1016/j.rser.2008.08.002
1.Introduction
Water heating is the fourth largest energy user in the commercial buildings sector,after heating,air conditioning,and lighting.It is a major energy user in building types such as full-service restaurants,motels and hotels,assisted living centers,and other facilities that do a great deal of laundry or dishwashing [1].
Water heating accounts for 17%of all residential site energy use in the United States,making it the third largest use of energy in homes.That percentage varies somewhat,with the average home in some states (e.g.,California)using 25%of its energy for water heating.Nearly 40%of all homes in the https://www.doczj.com/doc/3e11311459.html,e electricity to heat water.Again,that fraction varies considerably from state to state,with more than 80%of homes in some states (e.g.,Florida)and less than 15%of others (e.g.,California and New York)using electric water heaters (WHs)[2].
Most residential WHs are equipped with conventional heaters generating heat by consuming fossil fuels or electricity.Those WHs are usually simple,but not desirable in view of energy utilization ef?ciency.For instance,electric WHs are convenient for installa-tion and operation,however,the overall ef?ciency in converting a potential energy of fossil fuels into electric energy,then into thermal energy is quite https://www.doczj.com/doc/3e11311459.html,pared to those WHs,heat pump (HP)water heating systems can supply much more heat just with the same amount of electric input used for conventional heaters [3].
HP systems are heat-generating devices that can be used to heat water to be used in either domestic hot water or space heating applications.For HP,a basic factor of great importance for its successful application is the availability of a cheap,dependable heat source for the evaporator-preferably one at relatively high temperature.The coef?cients of performance (COP)of HP systems depend on many factors,such as the temperature of low-energy source,the temperature of delivered useful heat,the working medium used,the characteristics of components of HP systems,etc.Among the above mentioned,the temperature of the evaporator is a key factor [4].
Since the 1950s,researches have been performed on heat pump water heaters (HPWHs),including structure,thermodynamics,working ?uids,operation controlling,numerical simulation and economical analysis [5–7].
Kim et al.[3]designed a dynamic model of a WH system driven by a HP to investigate transient thermal behavior of the system which was composed of a HP and a hot water circulation loop.From the simulation,the smaller size of the water reservoir was found to have larger transient performance degradation,and the larger size caused additional heat loss during the hot water storage period.Therefore,the reservoir size should be optimized in a
Nomenclature A surface area (m 2)
C speci?c heat (kJ/kg K)
COP heating coef?cient of performance cos w power factor
˙E energy rate (kW)˙Ex exergy rate (kW)
f friction factor or exergetic factor (%)˙F exergetic fuel rate (kW)h speci?c enthalpy (kJ/kg)
I current (A),global irradiance (W/m 2)I ˙P improvement potential rate (kW)
˙I irreversibility (exergy destruction)rate (kW)˙m mass ?ow rate (kg/s)P pressure (kPa)
˙P exergetic product rate (kW)s speci?c entropy (kJ/kg K)˙S entropy rate (kW/K)˙Q heat transfer rate (kW)T temperature (K or 8C)V voltage (V)
˙W
rate of work or power (kW)
Greek letters d fuel depletion rate (%)e exergy (second law)ef?ciency h energy ef?ciency j productivity lack (%)x relative irreversibility (%)c speci?c exergy (kJ/kg)Subscripts
act actual avg averaged
c space cooling coll collector comp compressor con
d condenser
cw space cooling and water heating dest destroyed (destruction)dhwt domestic hot water tank e evaporation elec electrical evap evaporator
exp expansion (throttling)valve fc fan-coil
fh ?oor heating
fhs ?oor heating system gen generation
ghe ground heat exchanger GSHP ground-source heat pump h heating HP heat pump
i each unit value in input,inlet k
location mech
mechanical
out outlet,output p pressure r refrigerant scol solar collector
SDHWS solar domestic hot water system sh space heating sr solar radiation t thermal T total u useful w
water over dot rate
0reference (dead)state
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design process to minimize both the heat loss and the performance degradation.
Laipradit et al.[8]investigated theoretical performance analysis of HPWHs using carbon dioxide as refrigerant.For rated capacities of a4kW compressor with a10kW gas cooler and a6kW evaporator,the coef?cient of performance is found to be between 2.0and3.0.The mass?ow rate ratio of water and CO2between1.2 and 2.2is the most suitable value for generating hot water temperature above608C at15–258C ambient air temperature.
Rankin et al.[9]presented a study about demand side management for commercial building using an inline HPWH methodology.Rousseau and Greyvenstein[10]also performed enhancing the impact of HPWH in the South African commercial sector.
The main objectives in doing the present study are:(i)to review studies conducted on HPWH systems taking into consideration the analysis that have been made(theoretical–experimental,energy–exergy)and the utilization of the systems(space heating,water heating,air conditioning(A/C)),(ii)to present a mathematical model for exergy-based HPWH calculations including thermo-dynamic parameters,such as fuel depletion ratio,relative irreversibility,productivity lack and exergetic factor as well as improvement potential,and(iii)to apply the present mathema-tical model to an illustrative example.
2.A brief description of HPWH technology
HPWHs are a promising technology and use the same mechanical principles as refrigerators and air conditioners.While refrigerators remove heat from the interior and discharge it to the (kitchen)environment,HPWHs take heat from the environment and concentrate it to heat water for service needs[1].
A HP is a machine that transfers heat from a source to other by employing a refrigeration cycle.Although heat normally?ows from higher to lower temperatures,a HP reverses that?ow and acts as a‘‘pump’’to move the heat.Therefore,a HP can be used both for space heating in the winter and for cooling(air conditioning)in the summer.In the refrigeration cycle,a refrigerant(known as the ‘‘working?uid’’)is compressed(as a liquid)then expanded(as a vapor)to absorb and remove heat.The HP transfers heat to a space to be heated during the winter period and by reversing the operation,extracts(absorbs)heat from the same space to be cooled during the summer period[11].
Fig.1illustrates the schematic of a simpli?ed HPWH system, while the current status of the HPWH technology,its savings potential,its potential?nancial attractiveness to consumers,and market barriers to signi?cant penetration into the market have been given in more detail in Ref.[2].
The HPWH removes heat from the ambient air and puts it into a water storage tank.This process produces cooler,dryer(depending on relative humidity)exhaust air than the source air.Therefore, placement of the HPWH relative to the conditioned space affects overall building energy use.A HPWH has an easier time generating 608C water if the ambient air is248C than if it is1.78C.Once the ambient temperature drops below a certain threshold(depending on the con?guration of the unit and the refrigerant,this is typically around08C),the HP can no longer extract meaningful heat,and an electric resistance back-up element is employed.As the tempera-ture approaches this threshold,the condenser must go through defrost cycles to clear accumulated ice,and this lowers ef?ciency. Additionally,HPWHs typically have a longer recovery rate than electric resistance units,which necessitates larger tank size.
HPWHs can be used for heat water only or multi-functional purposes.Many researchers have presented different systems and analyzed their ef?ciencies.For example,these systems include air-source heat pumps(ASHPs),ground-source heat pumps(GSHP), solar-assisted heat pumps,direct-expansion solar-assisted heat pump(DX-SAHPs),integrated solar-assisted HPs,gas engine driven heat pumps(GEHPs)and multi-function HPs.
As for as ef?ciencies of HPWHs are concerned,HPWHs have an energy factor(EF)of between2and3,depending on the unit(EF is used to rate the energy ef?ciency of storage-type hot WHs;the higher the EF,the more ef?cient the unit).This suggests savings relative to standard new electric resistance WHs(whose EFs are typically close to0.9)of55–70%.However,multiple?eld test data indicate that actual water heating energy savings relative to standard electric resistance WHs are40–60%.There are several factors that contribute to this,including recharge rate,defrost cycles,and inlet water and ambient air temperatures.As a result of the fact that the HPWH uses ambient air to heat the water and then exhausts cooler and dryer air,the placement of the unit within the conditioned space has an impact on the building’s heating,cooling, and dehumidi?cation energy use[2].
3.A brief historical development of heat pumps and HPWHs
The use of HPs for the heating and cooling of the Equitable Building,initiated in1948,was a pioneering achievement in the Western hemisphere.The theoretical conception of the HP was described in a neglected book,published in1824,and written by a young French army of?cer,Sadi Carnot.Its practical application on a large scale is attributable to designers J.Donald Kroeker and Ray C.Chewning;building engineer,Charles E.Graham,and architect Pietro Belluschi[12].
The tremendously gifted Irish scientist William Thomson(Lord Kelvin)is usually credited with the concept of the HP,though he did not have the resources to construct one.The?rst patent for this device was awarded in1927to T.G.N.Haldane,an English inventor [13].
In1948if one were to predict the site of the?rst commercial HP installation in the US,Portland,Oregon would probably not even be on the list.Located in the north end of the Willamette Valley,the con?uence of the Willamette River and the Columbia River, Portland enjoys a moderate climate.Winter average temperature is approximately388,while the summer average is648F.In1948 the standard for building design because of the moderate temperatures in the summertime,did not require air conditioning in the Willamette Valley[12].
Commercial distribution of HP units,which was initiated in the early1950s,suffered declines in the1960s due to a record of poor reliability,but registered rapid growth after1970,when higher electricity costs made electric furnaces less competitive,and improved quality control increased the attractiveness of
HPs. Fig.1.Schematic of a simpli?ed HPHW system[2].
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The oil crisis in the beginning of the 1970s has led researchers to use alternative energy sources for energy production [4].Later,HPs became popular for heating and cooling applications and ground source,air source,combining solar energy and GEHPs were proposed by many researchers [14].
In 1996,the world’s largest installation of geothermal HPs was completed at the U.S.Army’s Fort Polk military base in Leesville,Louisiana.The HPs replaced 3243ASHPs and 760central air conditioning/natural gas forced air furnace systems for 4003housing units.The housing units were apartments,townhouses,and duplexes built between 1972and 1988.Unit ?oor space ranged from about 84to 130m 2.The geothermal HP con?guration implemented at Fort Polk is a closed-loop,vertical-borehole ground heat exchanger system.Each HP has its own ground heat exchanger of the vertical U-tube type of polyethylene pipe.Over 8000borehole heat exchangers were drilled.Each borehole has a 4-in.diameter and a depth of about 30–137m [15].
HPs,involving higher initial costs than electric furnaces,are attractive as long as their ef?ciency (200%or more)provides an eventual return on the investment.Solar heating systems,with high seasonal ef?ciencies (400–600%),nevertheless may not be attractive investments if initial costs are very high [14].4.Reviewing and classifying studies conducted on HPWHs In the following section,various types of HPWHs are reviewed and classi?ed in terms of applications,including some experi-mental data on operating and performance.4.1.Reviewing studies conducted
Swardt and Meyer [16]studied on the performance of a reversible GSHP coupled to a municipality water reticulation system,compared experimentally and with simulations to a conventional ASHP for space cooling and heating.GSHPs have demonstrated the potential to reduce peak demands and total electricity consumption.The use of a municipality water reticula-tion system as a heat source/sink resulted in an annual improvement of 13%in capacities and an annual improvement of 14%in COPs.Especially at low ambient air temperatures,GSHPs have signi?cant heating capacity (24%)and ef?ciency improve-ments (20%)over ASHPs.The schematic diagram is shown in Fig.2.
Hepbasli et al.[17]performed for the ?rst time in Turkey at the university level the performance characteristics of a GSHP system with a 50m vertical 11/4in.nominal diameter U-bend ground heat exchanger.This system was installed in a 65-m 2room in the Solar Energy Institute,Ege University,Izmir (568degree days cooling,base:228C,1226degree days heating,base:188C),Turkey.The heating and cooling loads of the room were 3.8and 4.2kW at design conditions,respectively.The system was commissioned in
May 2000and performance tests have been conducted since then.Based upon the measurements made in the heating mode,the heat extraction rate from the soil,with an average thermal diffusivity of 0.00375m 2/h,was found to be,on average,11W/m of bore depth,while the required borehole length in meter per kW of heating capacity was obtained to be 14.7.The entering water temperature to the unit ranged from 5.5to 13.28C,with an average value of 88C.The heating coef?cient of performance of the HP and the whole system was extremely low when compared to other HPs operating under conditions at or near design values (Fig.3).
Various means of producing domestic hot water (DHW)with renewable energy in zero net energy homes (ZNEH)were
examined for two climates (Montre
′al and Los Angeles)by Biaou and Bernier [18].Four alternatives investigated included (i)a regular electric hot water tank;(ii)the desuperheater of a GSHP with electric backup;(iii)thermal solar collectors with electric backup;and (iv)a HPWH indirectly coupled to a space condition-ing GSHP,as can be seen in Fig.4.Results indicated that heating DHW with thermal solar collectors with an electric backup (which is either provided by the photovoltaic (PV)panels or the grid in a ZNEH)was the best solution for a ZNEH.The second part of this paper focused on determining what should be the respective areas of the thermal solar collectors and PV array to obtain the least expensive solution to achieve total DHW production with renew-able energy.
The most common type of HP for domestic use,referred to as a ‘‘conventional’’HP,is the air-to-air (air source)system in which heat is taken from air (heat source)at one location and transferred to air (heat sink)at another location.In the winter,a HP takes heat from outside air and via a working ?uid transports the heat to inside the home.When the outside air temperature drops below à3.88,à1.18C,the ASHP uses electric resistance heat.In the summer,the HP reverses the process,removing heat from the home and transporting it to outside air,cooling the home in the process [11].There have been many studies conducted on ASHP.
One of them,a pilot run facility for assembly and testing of 100units was designed and constructed.After assembly and shipment,these 100units were placed in customers’homes by 20electric utility companies in order to demonstrate the capabilities of the HPWH.The performance of the units was being monitored for 1year by these utilities;the data would be forwarded to energy utilization systems (EUS)and would be presented in a ?nal report by Harris et al.[2]and Sloane et al.[19].Two HPWH models have been developed.One model was designed as a complete unit,consisting of a HP assembly mounted at top a 0.31-m 3water tank.The second model was a retro?t unit,designed to be used with an existing WH installation.The ?rst model is demonstrated in Fig.5.The COP values ranged from about 2.0at 188C ambient air and 278C source water,to about 2.8at 358C ambient air and 4.48C source water.
Harata et al.[20]used thermoelectric technology.The thermo-electric technology changing electric energy into the heat energy was commonly known to be used as the HP.In this thermoelectric technology,they used a HP utilizing the latent heat of the atmosphere.The other characteristic was to collect the heat occurring from the power supply equipment of the thermoelectric technology device in effect a combined heat and power (CHP)device.In this thermoelectric technology,an improvement of the energy ef?ciency could be expected.Initially they examined for a basis a bench scale model.As for examination condition,the capacity of the tank was 3.7l,the temperature of hot water was 858C,the environment temperature was 238C and the ef?ciency of the power supply was 80%(Fig.6).
Ito and Miura [21]investigated the mechanism of HPs for hot water supply using dual heat sources of the ambient air and
water
Fig.2.Cycle layout [16].
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and the operating conditions of selecting either one or both heat sources.Then,the performance of a HP,which used water and the ambient air as the heat sources to heat water,was experimentally studied.When the temperature of the water heat source was decreased,the heat from the water as well as the heat from the air was used for the HP ef?ciently until its temperature became approximately that of the evaporation temperature of the HP using the ambient air alone as the heat source.When the temperature of the water dropped further,only the heat from the air was absorbed by the evaporators like an ordinary HP,which used only the evaporator of the air heat source at the same ambient air temperature.The system is illustrated in Fig.7.
Ji et al.[22]introduced a novel air-conditioning product,that could achieve the multi-functions with improved energy perfor-mance.They reported the basic design principles and the laboratory test results.The results showed that by incorporating a WH in the outdoor unit of a split-type air-conditioner,so that space cooling and water heating could take place simultaneously,the energy performance could be raised considerably.Two prototypes of slightly different design were fabricated for performance testing (Figs.8and 9).Averaged COP,for space cooling and water heating,water heating only and space heating only,was obtained 4.02,2.91,2.00(ambient temperature at 4.58C)and 2.72,respectively.
One the other study,seasonal performance evaluation methods for WHs was reviewed,while an experimental method for rating ASHPWHs was presented by Morrison et al.[23].The rating method was based on the measured HP performance during the heat-up operation of particular products rather than a generic simulation model of HP performance.The measured performance was used in a correlation model of the HP unit in an annual load-cycle system performance simulation based on the TRNSYS simulation package.The two ASHPWHs tested had signi?cantly lower performance than typical solar WHs or solar-boosted HPWHs.They could be used in applications where solar WHs cannot be considered.These schematic diagrams are given in Figs.10and 11.
Zhang et al.[5]dealt with the system optimization of ASHPWH,including calculating and testing (Fig.12).The ASHPWH system consisted of a HP,a water tank and connecting pipes.Air energy was absorbed at the evaporator and pumped to storage tank via a Rankine cycle.The coil pipe/condenser released condensing heat of the refrigerant to the water side.An ASHPWH using a rotary compressor heated the water from initial temperature to the set temperature (558C).The capillary tube length,the ?lling quantity of refrigerant,the condenser coil tube length and system matching were discussed accordingly.
One other type HP is solar-assisted HP.The oil crisis in the beginning of the 1970s has led researchers to use alternative energy sources for energy production.Solar energy was the ?rst https://www.doczj.com/doc/3e11311459.html,ter,when HPs became popular for heating and cooling applications,combining solar energy and HPs in several ways
were
Fig.3.Isometric stand:(1)ground heat exchanger;(5)brine circulating pump;(7)water circulating pump;(9)heat exchanger;(10)heat exchanger;(12)capillary tube;(15)desuperheater;(17)compressor;(19)fan-coil units [17].
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proposed by many researchers.Although the idea of a DX-SAHP was ?rst proposed by Sporn and Ambrose in 1955,because the ?rst main studies on the subject began at that date,the beginning of the studies on DX-SAHP systems is therefore accepted as the late 1970s [4]
.
Fig.4.Schematic representation of the ZNEH [18]
.
Fig.5.Cutaway view of a heat pump water heater [2,19]
.Fig.6.Heat up stage [20].
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Sakai et al.[24]described a speci?c HP system that could solve the problem of low heating capacity at a low ambient temperature one of the largest problems in the ASHP system.In order to decrease the collector area required,the HP system was operated by the air-source during the daytime,but at night or at a very low ambient temperature it could be operated with hot water,which has been produced by the collector in the daytime.The effect of the solar energy on the ASHP system had many advantages in the moderate winter climate of Japan.The hot water supply system included an auxiliary electric heater.The experiment had been carried out with a prefabricated test house,which had been constructed in Nara with double glazed windows and high thermal insulation.The results of this experiment were that solar energy enhanced the total electric energy savings,increased the heating capacity at low ambient temperature,and eliminated the need for reverse cycle defrosting operation,etc.
A variable capacity direct-expansion solar-assisted HP system was developed and operated for DHW application by Chaturvedi et al.[25].The proposed system employed a bare solar collector which also acted as the system evaporator.A variable frequency drive modulated the compressor speed to maintain a proper matching between the heat pumping capacity of the compressor and the evaporative capacity of the collector under widely varying ambient conditions (Fig.13).Experimental results indicated that the coef?cient of performance of the system could be improved signi?cantly by lowering the compressor speed as ambient temperature rises from winter to summer months.
Chaichana et al.[26]presented the comparative assessment of natural working ?uids with R-22in terms of their characteristics and thermo physical properties,and thermal performance.Some justi?cation was given for using natural working ?uids in a solar-boosted HPWH.The results showed that R-744was not suitable for solar-boosted HPs because of its low critical temperature and high operational pressures.On the other hand,R-717seemed to be a more appropriate substitute in terms of operational parameters and overall performance.R-290and R-1270were identi?ed as candidates for direct drop-in substitutes for R-22.
A solar-assisted HP dryer and WH were designed,fabricated and tested by Hawlader et al.[27].The performance of the system had been investigated under the meteorological conditions of Singapore.A simulation program was developed using Fortran language to evaluate the performance of the system and the in?uence of different variables (Fig.14).The performance indices considered to evaluate the performance of the system included solar fraction (SF)and COP with and without a WH.The values of COP,obtained from the simulation and experiment were 7.0,and 5.0,respectively,whereas the SF values of 0.65and 0.61were obtained from simulation and experiment,respectively.
Chyng et al.[28]carried out a modeling and system simulation of an integral-type solar-assisted heat pump water heater (ISAHP).The schematic diagram is shown in Fig.15.The modeling and simulation assumed a quasi-steady process for all the components in the ISAHP except the storage tank.The simulation results for instantaneous performance agreed very well with experiment.
The
Fig.7.Heat pump using dual heat sources in parallel arrangement for evaporation [21]
.
Fig.8.Working cycles of the two-function air-conditioner [22].
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simulation technique was used to analyze the daily performance of an ISAHP for 1year.It was shown that the daily total COP was around 1.7–2.5year around for the ISAHP,depending on seasons and weather conditions.
Analytical and experimental studies were performed on a DX-SAHP water heating system,in which a 2m 2bare ?at collector acted as a source as well as an evaporator for the refrigerant by Kuang et al.[29].A simulation model was developed to predict the long-term thermal performance of the system approximately.The
monthly averaged COP was found to vary between 4and 6,while the collector ef?ciency ranged from 40to 60%(Fig.16).
Huang et al.[30]studied a heat-pipe enhanced solar-assisted heat pump water heater (HPSAHP).HPSAHP is a heat pump with dual heat sources that combines the performance of conventional heat pump and solar heat-pipe collector.HPSAHP operates in heat-pump mode when solar radiation is low and in heat-pipe
mode
Fig.9.Working cycles of the three-function air-conditioner [22]
.
Fig.10.Air-source heat pump water heater with wrap-around condenser coil [23]
.Fig.11.Air-source heat pump water heater with external condenser [23].
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without electricity consumption when solar radiation is high.HPSAHP can thus achieve high energy ef?ciency.A prototype was designed and built in the present study.An outdoor test for a HPSAHP in the present study has shown that COP of the hybrid-mode operation can reach 3.32,an increase of 28.7%as compared to the heat-pump mode COP (2.58).The schematic diagram is shown in Fig.17.
Guoying et al.[31]presented a simulation study on the operating performance of a new type of solar-air source heat pump water heater (SAS-HPWH).The SAS-HPWH used a specially designed ?at-plate heat collector/evaporator with spiral-?nned tubes to obtain energy from both solar irradiation and ambient air for hot water https://www.doczj.com/doc/3e11311459.html,ing the meteorological data in Nanjing,China,the simulation results based on 150l water heating capacity showed that such a SAS-HPWH could heat water up to 558C ef?ciently under various weather conditions all year around.This schematic diagram is illustrated in Fig.18.
One another study (Fig.19)on DX-SAHP was conducted by Li et al.[32].A direct-expansion solar-assisted heat pump water heater (DX-SAHPWH)experimental set-up was introduced and analyzed.This DX-SAHPWH system mainly consisted of 4.20m 2direct-expansion type collector/evaporator,R-22rotary-type hermetic compressor with rated input power 0.75kW,150-l water tank with immersed 60-m serpentine copper coil and external balance type thermostatic expansion valve.The experi-mental research under typical spring climate in Shanghai showed that the COP of the DX-SAHPWH system could reach 6.61when the average temperature of 150l water was heated from 13.4to 50.58C in 94min with average ambient temperature 20.68C and average solar radiation intensity 955W/m 2.The COP of the DX-SAHPWH system was 3.11even if at a rainy night with average ambient temperature 17.18C.The seasonal average value of the COP and the collector ef?ciency were measured to be 5.25and 1.08,respectively.
Hepbasli [33]studied on the exergetic modeling and perfor-mance evaluation of solar-assisted DHW tank integrated
GSHP
Fig.12.Sketch of the experimental system to test the performance of ASHPWH:(1)shell body;(2)heat exchanger;(3)fan;(4)store;(5)compressor;(6)?lter;(7)valve;(8)thermal expansion valve;(9)copper pipe;(10)outer shell;(11)thermal insulation;(12)inner tank;(13)coil pipe condenser;(14)temperature and humidity controlled room;(15)inlet water pipe;(16)cycle water pump;(17)water mixing valve;(18)three way valve;(19)outlet water pipe;(20)controller;(21)ammeter;(22)computer;(23)data scrutiny;(24)data logger;(25)hot water tank;(26)cycle water pipe;A–H:temperature sensors;I,J:water meters [5]
.
Fig.13.Schematic of DX-SAHP system [25].
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systems for residences (Fig.20),while he used the existing energetic data given by Trillat-Berdal et al.[34].Exergy ef?ciency values on a product/fuel basis were found to be 72.33%for the GSHP unit,14.53%for the solar DHW system and 44.06%for the whole system at dead (reference)state values for 198C and 101.325kPa.Exergetic COP values were obtained to be 0.245and 0.201for the GSHP unit and the whole system,respectively.The greatest irreversibility (exergy destruction)on the GSHP unit basis occurred in the condenser,followed by the compressor,expansion valve and evaporator.
One other type HPs are new technology GEHPs.Although GEHP was appeared on the Japanese HVAC marketplace in 1986
and
Fig.14.Schematic diagram of heat-pump assisted solar-dryer and water heater:(AUX)auxiliary heater;(AC)air collector;(B)blower;(COMP)compressor;(COND)condenser;(CT)condenser tank;(D)damper;(DRY)dryer;(EV1)evaporator 1;(EV2)evaporator 2;(EX)expansion valve;(TC)thermocouple;(PID)temperature controller;(-)air path;(--)refrigerant path;(PR)pressure regulator;(FCU)fan-coil unit [27]
.
Fig.15.Schematic diagram of the integral-type solar-assisted heat pump [28].
A.Hepbasli,Y.Kalinci /Renewable and Sustainable Energy Reviews 13(2009)1211–1229
1220
water-loop heat pump system (WLHPS)even as early as 1960s in the USA,the combination of GEHP and WLHPS is completely a new conception of their application [35].
A GEHP usually consists of a reversible vapor compression HP with an open compressor driven by a gas fueled internal combustion engine instead of an electric motor.The GEHP has been paid more attention in the heating,ventilation and air conditioning (HVAC)?eld in recent years due to its advantage of reducing the electric consumption in the cooling and heating seasons.Another two distinguished advantages of the GEHP are (1)the ability to recover the waste heat released by the engine cylinder jacket and exhaust gas in the heating mode and (2)the easy modulation of compressor speed by adjusting the gas supply.Therefore,the GEHP has a different performance from that of the electric driven heat pump (EHP),especially in the heating mode [36].
Conception of combination of GEHP and WLHPS was ?rstly presented by Lian et al.[35]in order to reduce the energy consumption of air conditioning system further.Design of the new system was introduced through an actual project in China
and
Fig.16.Schematic diagram of the DX-SAHP water heater [29]
.
Fig.17.Flow chart and schematic diagram of the HASHP [30].
A.Hepbasli,Y.Kalinci /Renewable and Sustainable Energy Reviews 13(2009)1211–12291221
compared with a conventional air-conditioning system (CACS)and conventional WLHPS (EHP-WLHPS)in terms of technical char-acteristics and payback period.It was found that the payback period of GEHP-WLHPS was about 2years when compared with CACS and 2.6years with EHP-LHPS on the average.The schematic diagram is shown in Fig.21.
Zhang et al.[36]analyzed the heating performance of a gas engine driven air to water HP using a steady state model (Fig.22).The thermodynamic model of a natural gas engine was identi?ed by the experimental data,while the compressor model was created by several empirical equations.The heat exchanger models were developed by the theory of heat balance.The system model was validated by comparing the experimental and simulation data,which indicated good agreement.The results showed that engine waste heat could provide about 1/3of the total heating capacity in this gas engine driven air to water HP.The performance of the engine,HP and integral system were analyzed under variations of engine speed and ambient temperature.It indicated that engine speed had remarkable effects on both the engine and HP,but ambient temperature had little in?uence on the engine’s performance.
Lazzarin and Noro [37]analyzed ‘‘S.Nicola’’HVAC plant in Vicenza features and signi?cant energy savings characteristics (Fig.23).It has been set up by a GEHP (coupled to two condensing boilers)whose performances were evaluated during 3years of operation.In the following analysis only the heating and
cooling
Fig.18.The schematic diagram of the simulated SAS-HPWH [31]
.
Fig.19.Schematic of system circuit [32].
A.Hepbasli,Y.Kalinci /Renewable and Sustainable Energy Reviews 13(2009)1211–1229
1222
plant had been considered.The main component was reversible air/water GEHP.The nominal cooling power was 275kW (22Nm 3/h of natural gas was the nominal fuel consumption),while in heating mode the output power was 380kW (19Nm 3/h fuel consumption).These performances were labeled for summer external air 358C and evaporator input/output 12/78C;winter external air 108C and condenser input/output 40/458C.Heat recovery was taken from the lubricating oil,engine cooling water and partly from the exhaust.The nominal power thus recovered was 109kW in heating mode and 127kW in cooling mode,to produce hot water at about 708
C.
Fig.20.Schematic view of a solar-assisted domestic hot water tank integrated GSHP system [33,34]
.
Fig.21.Schematic view of the outdoor unit of a GEHP [35].
A.Hepbasli,Y.Kalinci /Renewable and Sustainable Energy Reviews 13(2009)1211–12291223
Historical development of GEHP systems was brie?y given by Hepbasli et al.[38].Next,the operation of these systems was described,while studies conducted on them were reviewed and presented in tabulated forms.GEHPs were then modeled for performance evaluation purposes by using energy and exergy analysis methods.Finally,an illustrative example was given.
4.2.Classifying studies conducted
A detailed review of studies conducted on HPWH systems is given in Table 1.As can be seen from the table,HPWH systems were evaluated under four groups,GSHP,ASHP,solar-assisted HP and GEHP,
respectively.
Fig.22.Schematic diagram of GEHP:(1)natural gas engine,(2)open compressor,(3)four-way valve,(4)plate heat exchanger,(5)supply water pump,(6)expansion valve,(7)?nned-tube heat exchanger,(8)heat radiator,(9)gas-to-water heat exchanger,(10)three-way valve,(11)water-to-water heat exchanger,(12)cooling water pump,(13)three-way valve [36]
.
Fig.23.Schematic view of the gas engine heat pump installed in the ‘‘S.Nicola’’HVAC plant (values reported refer to heating mode)[37].
A.Hepbasli,Y.Kalinci /Renewable and Sustainable Energy Reviews 13(2009)1211–1229
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The performance indicator for HP systems,namely COP values,varied from 0.201to 6,while most of the values were between 2and 3.
Most of the systems were used in water-heating applications,space heating and A/C performances.Since energy was mainly used for water and space-heating purposes in many countries,studies related with improving the performances and reducing costs in such applications played an important role,also providing less demand for fossil fuels.Theoretical and experi-mental analysis as well as energy analysis were conducted by nearly all of the studies,while exergy analysis was covered by very few of them.
Comparison of WHs is seen in Table 2.According to the table,the most ef?ciency WH types are HP and solar with electric back-up with energy savings vs.minimum standards,65%and 70–90%,respectively.Expected life time for these systems are 10and 20years,while major advantages are most ef?cient electric fuel option and largest energy savings using a renewable energy source,respectively [39].5.Modeling
Energy and exergy analysis is presented for the performance evaluation of the HPWH systems.Balance (mass,energy and exergy)equations for steady state,constant-?ow control volume systems,and appropriate energy and exergy equations are derived for these systems and its components [32,40,41].5.1.General energy and exergy balance equations
The mass balance equation can be expressed in the rate form as X ˙m in ?X
˙m out (1)where ˙m
is the mass ?ow rate,and the subscript in stands for inlet and out for outlet.
The general energy and exergy balances can be expressed below as the total energy and exegy inputs equal to total energy and exergy outputs,respectively.X ˙E in ?X
˙E out (2)X ˙Ex
in àX
˙Ex
out ?X
˙Ex
dest (3a)
or
˙Ex
heat à˙Ex work t˙Ex mass ;in à˙Ex mass ;out ?˙Ex dest (3b)
Using Eq.(3b),the rate form of the general exergy balance can also be written as
X 1àT 0k
˙Q k à˙W tX ˙m in c in àX ˙m out c out ?˙Ex dest (4)with
c ?eh àh 0TàT 0es às 0T
(5)
where ˙Q
k is the heat transfer rate through the boundary at temperature T k at location k,˙W
is the work rate,c is the ?ow (speci?c)exergy,h is enthalpy,s is entropy,and the subscript zero indicates properties at the restricted dead state of P 0and T 0.
Multiplying ?ow or speci?c exergy given in Eq.(5)by the mass ?ow rate of the ?uid gives the exergy rate:˙Ex
?˙m ?eh àh 0TàT 0es às 0T (6)
Also,it is usually more convenient to ?nd ˙S
gen ?rst and then to evaluate the exergy destroyed or the irreversibility rate ˙I directly from the following equation,which is called Gouy–Stodola relation:
˙I ?˙Ex
dest ?T 0˙S gen (7)
Furthermore,mass,energy and exergy equations are demonstrated
in Table 3for each components.5.2.Improvement potential
Van Gool [42]has also proposed that maximum improve-ment in the exergy ef?ciency for a process or system is obviously achieved when the exergy loss or irreversibility e˙Ex
in à˙Ex out Tis minimized.Consequently,he suggested that it is useful to employ the concept of an exergetic ‘‘improvement potential ’’when analyzing different processes or sectors of the economy.This improvement potential in the rate form,denoted I ˙P
,is given by I ˙P
?e1àe Te˙Ex in à˙Ex out T(8)
5.3.Some thermodynamic parameters
Thermodynamics analysis of thermal and HPWH systems may also be performed using the following parameters [43]: Fuel depletion ratio:
d i ?
˙I i F
T (9)
Relative irreversibility:
x i ?
˙I i ˙I T
(10)
Table 2
Comparison of water heaters [39]High ef?ciency water heater type
Energy savings vs.minimum standards
Best climates
Expected energy savings over equipment lifetime (US$)Expected
lifetime (years)
Major advantages
High ef?ciency storage (tank)(oil,gas,elec.)10–20%Any Up to 5008–10Lowest ?rst cost
Demand (tankless)using gas or elec.45–60%
Any Up to 180020Unlimited supply of hot water Heat pump 65%(compared to electric resistance)Mild-hot Up to 90010Most ef?cient electric fuel option Solar with electric back-up
70–90%
Mild-hot
Up to 2200
20
Largest energy savings using a renewable energy source
A.Hepbasli,Y.Kalinci /Renewable and Sustainable Energy Reviews 13(2009)1211–1229
1226
Productivity lack:
j i ?
˙I
i
˙P
T
(11)
Exergetic factor:
f i?˙F
i
˙F
T
(12)
6.Conclusions
HPWHs,unlike conventional WHs that use either gas burners (and sometimes other fuels)or electric resistance heating coils to heat the water,are devices,which operate on an electrically driven vapor-compression cycle and pump energy from the air in its surroundings to water in a storage tank,thus raising the temperature of the water.Its primary advantage is a signi?cant increase in point-of-use operating ef?ciency over alternative electric water-heating systems[44].
With water heating the second largest use of home energy in most locations,there has been renewed interest in the develop-ment and use of energy-conserving domestic WHs since the1973–1974oil embargo[45].
The main conclusions,which may be drawn from the results of the present study,are listed below:
(a)This study reviewed HPWHs in a period from1976to2007.
HPWHs were classi?ed in four main groups:GSHP;ASHPs;
solar-assisted HPs and GEHP.
(b)Both theoretical and experimental analyses done were much in
numbers.
(c)Energy analysis method was used in many studies,while the
number of studies conducted on exergy analysis was very low.
(d)Since space heating and A/C applications have more require-
ments,many of the systems are to be used in water heating applications.
(e)The performance indicator of GSHPs,namely COP,ranged from
1.656to3.307,considering cooling or heating aims.For ASHPs,
these values changed from1.8to5.66,according to ambient temperature,internal–external and water heating.
(f)Solar-assisted HP studies used different collectors,its ef?ciency
and COPs varied from0.08to 1.08and from 1.7to6, respectively.Only one study included exergy analysis,while its exergetic system ef?ciency and COP were44.06%and0.201, respectively.
(g)GEHP systems have become more ef?cient when used both in
water and space heating.
(h)When HPWHs are compared with other WHs,HPWHs are
second after solar with electric back-up.Their energy savings minimum standards,expected energy savings over equipment life time and expected life time are65%,up to900(US$)and10 years.
(i)HPWHs have considerable promise for use in both residential
and commercial applications.Residential HPWH units have been available for more than20years,but have experienced limited success in the marketplace.[1].
(j)Commercial-scale HPWHs are a very promising technology.
However,their present market share is extremely low,and only two or three manufacturers are seriously involved in the market.The market needs further conditioning for successful market transformation.The next step in this market con-ditioning is likely to be further demonstrations and developing additional,well-documented case studies that will support sales efforts to designers and customers[1].(k)At current production volumes,HPWH prices are beyond customers’likely willingness to pay,preventing widespread implementation of the product.This research indicates that the future of HPWHs is likely to be consistent with the past unless they are produced and sold in large enough quantities to reduce prices and increase availability.Policies or programs to promote ef?cient WHs may be necessary to make that happen
[2].
(l)By2020,annual electricity savings from HPWHs could be equal to between1%and2%(i.e.,12,000to24,000GW h)of total current residential electricity consumption in the U.S.That assumes an average national electric WH market share of a little less than20%to a little less than40%(or roughly25%to 50%of its‘‘target market’’)over the2007through2020time period[2].
Acknowledgements
The authors are grateful to their universities for the continued support in doing these kinds of studies.
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某娱乐中心冷冻站设计方案技术经济比较 对某给定工程冷冻站，拟定三种设计方案，分别采用水冷式水机组、风冷热泵式冷热水机组及溴化锂吸收式冷热水机组，从初投资、运行费、折旧费、控制、操作、噪声、振动、运行、管理等方面进行了技术经济比较，并从中选择一种付诸实施。前言 在空调技术快速发展的今天，工程设计中究竟选用哪一种冷（热）水机组？其经济性能、技术性能如何？本文以某工程为例，详细比较了水冷螺杆式冷水机组、风冷热泵螺杆式冷热水机组、直燃型溴化锂吸收式冷热水机组的经济技术性能，希望对工程设计中合理选择冷（热）水机组有所帮助。 工程概况及方案考虑 该娱乐中心为一座3层建筑，局部4层，建筑面积共5620m2。1层为冷冻站、厨房、中西餐厅、美容中心、浴室（内设冷、温、热水冲浪浴池，淋浴等）及客房（内设桑拿浴或按摩浴缸）。2层部分为KTV 包房，其余为客房。3、4层全部为客房。2、3、4层客房均有浴缸等卫生设施。 娱乐中心设有风机盘管空调系统和集中供卫生热水系统。本冷冻站即负担空调系统冷、热量供应和卫生热水系统热量供应。系统冷热负荷见表1。 冷热负荷表1 本工程考虑三个方案。 方案1 选用2台水冷螺杆式冷水机组，设计工况产冷量分别为490KW和324KW，合计814KW，夏季供空调系统冷量；选用一台燃油热水器，设计工况产热量1454KW，夏季供卫生热水系统热量，冬季供空调系统热量和卫生热水系统热量。 方案2 选用一台直燃型溴化锂吸收式冷热水机组，设计工况产冷量805KW，产热量678KW，夏季供空调系统冷量，冬季供空调系统热量；选用一台燃油热水器，设计工况产热量827KW，夏季、冬季供卫生热水系统热量。
风冷热泵的选型要点分享 根据风冷热泵的性能和系统分析各种泵的优缺点和适用范围，帮助我们很好选型。 一、根据风冷热泵的性能分析来选型: 1、风冷热泵的冷热量：这两个参数是决定风冷热泵正常使用的最关键参数，它是指风冷热泵的进风温度、进出水温度在设计工况下时其所具备的制冷量或制热量。它可从有关厂家提供的产品样本中查得。但目前在设计中也发现这样的情况，那就是有的厂商所提供的样本参数并未经过测试而是抄自其它厂家的相关样本。这给设计人员的正确选型带来了一定困难。因此笔者建议在有条件的情况下设计人员可根据有关厂家的风冷热泵所配置的压缩机型号，从压缩机生产厂家处获得该压缩机的变工况性能曲线，根据热泵的设计工况查得该压缩机在热泵设计工况下的制冷量和制热量，从而判断该样本所提供参数的真伪。 2、风冷热泵的COP值：该值是确定风冷热泵性能好坏的重要参数，其值的高低直接影响到风冷热泵使用中的耗电量，因此，应尽量选择COP值高的机组。目前我国国家标准是COP值为2.57，多数进口或合资品牌的COP在3左右，个别进口品牌的高效型机组其值可达到3.8。 3、噪声：噪声也是衡量一台风冷热泵机组的重要参数，它直接关系到热泵运行时对周围环境的影响。国内有关专家曾根据工程实测对各类进口热泵的噪声划分为三档，第一档在85dB以上、第二档在
75～85dB之间、第三档在75dB以下。我们在进行工程设计选型中应优先选择噪声在80dB以下的机组。 4、外型尺寸：风冷热泵机组大多布置在室外屋顶，它在进行设备布置时对设备与周围墙面的间距、设备之间的间距都有明确要求，因此我们在进行设备选型时必须考虑所选设备尺寸是否符合设备布置的尺寸要求。在性能相同的前提下应优先选用尺寸较小的机组，以减小设备的占地面积。 5、运行重量：由于风冷热泵机组大多布置在屋面，因此在选型时必须考虑屋面的承重能力，必要时应与结构专业协商，增强屋面的承重能力。但在设备选型时我们应优先选择运行重量较轻的机组。 二、根据风冷热泵的系统分析，了解各种泵的优缺点帮助选型： 所谓风冷热泵的系统分析，就是在风冷热泵的选型过程中除了比较各自的制冷量、制热量、COP值、噪声、运行重量、外形尺寸等参数外，还要对其各自的压缩机型式、冷凝器型式及布置、热力膨胀阀的配置、蒸发器型式、除霜方式、能量调节方式以及热泵系统的自控和安全保护等等加以分析，比较其各自在系统配置方面的优缺点。 压缩机的型式：目前用于风冷热泵的压缩机型式主要有活塞式、涡旋式、螺杆式三种型式。根据热泵工作的特点是运行时间长、压缩比大等情况，笔者认为涡旋式和螺杆式压缩机将成为热泵压缩机的主流。其理由是： 1、涡旋式和螺杆式压缩机较活塞式压缩机具有传动件少，从而使压缩机的磨擦损耗相应减少，整机的效率相应提高。暖通在线
风冷热泵冷热水机组选型应用 编者按：本文阐述了风冷热泵冷热水机组选型中应注意的几方面问题，并对其在工程设计中的几个应注意事项谈了体会。 风冷热泵冷热水机组是九十年代在我国开始应用的一种新型空调主机，此类机组既可供冷又可供热，省却了锅炉房和冷却水系统，安装灵活方便。机组运行采用微电脑控制，可靠性较高。因此在长江流域的许多空调工程中得以广泛采用。但由于各地气候条件不同，再加上工程设计方面也缺少经验。因此在使用中也发现了不少问题。 在进行一个工程的设计过程中，如果当地气候环境允许，同时经过技术经济分析比较后确定该工程空调冷热源采用风冷热泵机组，那么设计人员应该着手对国内外相关厂家的产品进行分析比较，为用户选择一款较为经济合理的热泵产品。选型的主要内容首先是机组的总体性能分析，它包括热泵机组的制冷量、制热量、COP值、噪声、外形尺寸、运行重量等参数。其次，分析该类热泵的内部配置，它包括压缩机型式、冷凝器结构及布置、热力膨胀阀的配置、蒸发器型式、能量调节方式、融霜方式、安全保护及自动控制项目等等。在进行上述分析比较后我们就可以选择一款较为理想的机组，接下来的工作就是进行设备布置，这过程中我们必须考虑设备之间的合理间距，辅助热源的配置以及多台热泵整体运行噪声对周围环境的影响等。下面就以上几方面的问题分别加以阐述。 风冷热泵的性能分析 风冷热泵的冷热量：这两个参数是决定风冷热泵正常使用的最关键参数，它是指风冷热泵的进风温度、进出水温度在设计工况下时其所具备的制冷量或制热量。它可从有关厂家提供的产品样本中查得。但目前在设计中也发现这样的情况，那就是有的厂商所提供的样本参数并未经过测试而是抄自其它厂家的相关样本。这给设计人员的正确选型带来了一定困难。因此笔者建议在有条件的情况下设计人员可根据有关厂家的风冷热泵所配置的压缩机型号，从压缩机生产厂家处获得该压缩机的变工况性能曲线，根据热泵的设计工况查得该压缩机在热泵设计工况下的制冷量和制热量，从而判断该样本所提供参数的真伪。 风冷热泵的COP值：该值是确定风冷热泵性能好坏的重要参数，其值的高低直接影响到风冷热泵使用中的耗电量，因此，应尽量选择COP值高的机组。目前我国国家标准是COP
风冷热泵机组 风冷热泵机组工作原理 风冷热泵机组特点 风冷热泵机组性能分析 风冷热泵机组系统分析 风冷热泵机组安全保护与控制 风冷热泵机组工程设计 风冷热泵机组工作原理 风冷热泵机组特点 风冷热泵机组性能分析 风冷热泵机组系统分析 风冷热泵机组安全保护与控制 风冷热泵机组工程设计 风冷热泵机组工作原理 风冷热泵机组是由压缩机——换热器——节流器——吸热器——压缩机等装置构成的一个循环系统。冷媒在压缩机的作用下在系统内循环流动。它在压缩机内完成气态的升压升温过程（温度高达100℃），它进入换热器后释放出高温热量加热水，同时自己被冷却并转化为流液态，当它运行到吸热器后，液态迅速吸热蒸发再次转化为气态，同时温度下降至零下20℃——30℃，这时吸热器周边的空气就会源源不断地将低温热量传递给冷媒。冷媒不断地循环就实现了空气中的低温热量转变为高温热量并加热冷水过程。 风冷热泵机组特点 1.风冷热泵机组属中小型机组，适用于200-10000平方米的建筑物。 2.空调系统冷热源合一，更适用于同时采暖和制冷需求的用户，同时省去了锅炉房。 3.机组户外安装，省去了冷冻机房，节约了建筑投资。 4.风冷热泵机组的一次能源利用率可达90%，节约了能源消耗，大大降低了用户成本。 5.无须冷却塔，同时省去了冷却水泵和管路，减少了附加设备的投资。 6.无冷却水系统动力消耗，无冷却水损耗，更适用于缺水地区。 风冷热泵机组性能分析 冷热量 这个参数是决定风冷热泵正常使用的最关键参数，它是指风冷热泵的进风温度、进出水温度在设计工况下时其所具备的制冷量或制热量。它可从有关厂家提供的产品
样本中查得。但目前在设计中也发现这样的情况，那就是有的厂商所提供的样本参数并未经过测试而是抄自其它厂家的相关样本。这给设计人员的正确选型带来了一定困难。因此笔者建议在有条件的情况下设计人员可根据有关厂家的风冷热泵所配置的压缩机型号，从压缩机生产厂家处获得该压缩机的变工况性能曲线，根据热泵的设计工况查得该压缩机在热泵设计工况下的制冷量和制热量，从而判断该样本所提供参数的真伪。 COP值 该值是确定风冷热泵性能好坏的重要参数，其值的高低直接影响到风冷热泵使用中的耗电量，因此，应尽量选择COP值高的机组。目前我国国家标准是COP值为2. 57，多数进口或合资品牌的COP在3左右，个别进口品牌的高效型机组其值可达到3.8。 噪声 噪声也是衡量一台风冷热泵机组的重要参数，它直接关系到热泵运行时对周围环境的影响。国内有关专家曾根据工程实测对各类进口热泵的噪声划分为三档，第一档在85dB以上、第二档在75～85dB之间、第三档在75dB以下。我们在进行工程设计选型中应优先选择噪声在80dB以下的机组。 外型尺寸 风冷热泵机组大多布置在室外屋顶，它在进行设备布置时对设备与周围墙面的间距、设备之间的间距都有明确要求，因此我们在进行设备选型时必须考虑所选设备尺寸是否符合设备布置的尺寸要求。在性能相同的前提下应优先选用尺寸较小的机组，以减小设备的占地面积。 运行重量 由于风冷热泵机组大多布置在屋面，因此在选型时必须考虑屋面的承重能力，必要时应与结构专业协商，增强屋面的承重能力。但在设备选型时我们应优先选择运行重量较轻的机组。 风冷热泵机组系统分析 风冷热泵机组的系统分析，就是在风冷热泵的选型过程中除了比较各自的制冷量、制热量、COP值、噪声、运行重量、外形尺寸等参数外，还要对其各自的压缩机型式、冷凝器型式及布置、热力膨胀阀的配置、蒸发器型式、除霜方式、能量调节方式以及热泵系统的自控和安全保护等等加以分析，比较其各自在系统配置方面的优缺点。 压缩机的型式：
风冷热泵选型及管网流程应用调整 摘要： 通过对风冷热泵机组的研究，了解其构造及基本选型，并根据工程需要对管网系统进行相应改进。 关键词： 模块式风冷热泵、螺杆式风冷热泵、管网流程、蓄水箱 一、引言 最近几年，随着科技的发展，国内的生物医药领域的研发实验室的建设越来越多，尤其是单克隆抗体或疫苗类型的研发实验室。 二、风冷热泵系统概况及选型 目前国内这些医药研发中心通常由办公室、普通实验室、净化实验室三个部分组成，总面积一般都不会太大，基本都控制在6000平方以内。对于办公区和普通实验区来说，中央空调一般都主要用来提供新风，能耗并不大。这两个区域的室内温度调节会通过风机盘管或多联机来满足要求。主要的能耗其实还是集中于净化实验区。 通常来说，在上海、北京、杭州这些国内中心城市，城市发展率较高，空间利用率要求也较高。作为研发性质的生物医药实验室来说，受空间和市政配套限制，不会单独考虑设置冷冻站和锅炉房来作为空调的冷热源，而会选择采用风冷热泵机组。因为风冷型热泵机组有其特点： 1、不需要冷却塔、冷却水泵及冷却水系统； 2、无需专用机房，可直接安装于屋顶或室外合适的空间。 3、智能控制：采用微电脑控制，具有故障诊断、能量管理、防冻监测等多项自动控制功能，确保机组高效运转，操作方便。机组自带485转换接口程序，机组可由上位计算机控制。各台机组的运行可由上位计算机根据负荷需求及运转时间来控制其启停。 4、重量轻、体积小，安装组合简单。 对此，有人可能会提出来一个问题，虽然说是选择风冷热泵，但是具体是选择哪一种风冷热泵呢？是选择模块式的风冷热泵机组、螺杆式风冷热泵机组、离
心式风冷热泵机组中的哪一种呢？ 具体来说，对于目前这种6000平方米以内规模的生物医药实验室来说，采用较多的是螺杆式风冷热泵机组或模块式风冷热泵机组这两种。至于说，具体采用这两种的哪一种，应该说都是可行的，只不过根据业主的考量的方向不一样，也就会有不一样的选择。 下面我来简单介绍一下这两种风冷热泵的特点： 模块式风冷热泵机组螺杆式风冷热泵机组 螺杆式风冷热泵：采用半封闭螺杆式高效压缩机，单机压缩，靠压缩机内的滑阀进行能量调节，结构紧凑，维护方便，运行稳定。出水温度稳定，受天气影响波动幅度小。 模块式风冷热泵机组：采用蜗旋式压缩机，每个模块机组里有2个压缩机，每台压缩机都是独立运行的，一台压缩机坏了，不影响别的压缩机继续使用。多台模块式风冷热泵可以组合在一起使用，一台机组坏了，不影响别的机组运行，控制系统能根据每台机组的运行时间自动调节机组起停，靠机组的运行台数或压缩机的运行个数来进行能量调节。出水温度较稳定，受天气影响波动幅度较小。 从上面两种机器的特性可以看出，如果更多的考虑空调冷冻水的出水温度的稳定性，那么，建议优先考虑螺杆式风冷热泵；如果对空调冷冻水的出水温度的变化幅度没有太高的要求，而重点考虑的是运行过程中能耗的节约，那么，建议优先考虑模块式风冷热泵。 其实，从我个人的角度来说，我建议再增加一个考量因素，那就是洁净室面积所占比重，若洁净室面积所占比重较大，建议优先考虑螺杆式风冷热泵，因为
致领导函 尊敬的XXX领导： 您好！ 非常感谢贵单位给我公司提供的这次参与空调系统说明的机会。多年来，清华同方秉承清华大学“自强不息、厚德载物”的校训，不以纯粹的出售产品为目的，而是以向广大顾客提供最适合其本身特点要求的服务为最高宗旨，竭尽全力、精益求精使企业取得了长足的发展，赢得了广泛的赞誉。 清华同方是具有新型空调设计、开发、制造、工程安装等综合服务能力为一体的高科技公司，以清华大学的高技术人才为依托，始终保持领先一步的技术优势。产品质量和工程安装质量也已在人民大会堂、故宫博物院、中央电视台、毛主席纪念堂、中国国际航空公司等数百项国家重大工程中经受住了严格的考验和检验。清华同方产品的先进性、质量的可靠性、服务的有效性已得到广泛的认证和中央领导人的认可。 我公司根据贵方工程概况及地理特点，本着合理、科学、用户至上的原则向贵方推荐： 二十一世纪最有效的供暖、空调技术 ——清华同方GHP型水源中央空调系统 2009年4月
二十一世纪最有效的供暖、空调技术 ——节能环保型水源热泵空调系统 地源热泵是一种利用地表浅层地热资源（也称地能，包括土壤、地下水和江、河、湖、海以及城市污水等）作为冷热源的即可供热又可制冷的高效、节能、环保的空调系统。地源热泵利用浅层地能温度相对稳定的特性，通过输入少量的高品位能源（如电能），使建筑达到供热或制冷的目的。地源热泵可以取代锅炉或市政管网等传统的供暖方式和中央空调系统。地能分别在冬季作为热泵供暖的热源和夏季空调的冷源，即在冬季，把地能中的热量“取”出来，提高温度后，供给室内采暖；夏季，把室内的热量取出来，释放到地能中去。地源热泵消耗1KW的能量，用户可以得到4KW以上的热量或冷量。同时，它还可以供应给生活用水，是一种有效地利用能源的方式。 污水、井水、费水、费冷、费热、综合利用 根据现场调查，特向甲方提供节能减排最佳方案： 1、夏季制冷时，抽取地下低温井水通过机组吸取水冷量后送至其它生产设备循环利用。 也可利用生产设备产生的费冷，通过机组吸收费冷循环利用。 2、冬季制热时，利用生产设备排出高温污水吸取热量后送至污水处理车间。
风冷热泵机组： 风冷热泵机组是由压缩机——换热器——节流器——吸热器——压缩机等装置构成的一个循环系统。冷媒在压缩机的作用下在系统内循环流动。它在压缩机内完成气态的升压升温过程（温度高达100℃），它进入换热器后与风进行热量交换，被冷却并转化为流液态，当它运行到吸热器后，液态迅速吸热蒸发再次转化为气态，同时温度下降至零下20℃——30℃，这时吸热器周边的空气就会源源不断地将低温热量传递给冷媒。冷媒不断地循环就实现了空气中的低温热量转变为高温热量并加热冷水过程。 特点： 1.风冷热泵机组属中小型机组，适用于200-10000平方米的建筑物。 2.空调系统冷热源合一，更适用于同时具有采暖和制冷需求的用户，省去了锅炉房。 3.机组户外安装，省去了冷冻机房，节约了建筑投资。 4.风冷热泵机组的一次能源利用率可达90%，节约了能源消耗，大大降低了用户成本。 5.无须冷却塔，同时省去了冷却水泵和管路，减少了附加设备的投资。 6.风冷系统替代冷却水系统，更适用于缺水地区。 性能： 冷热量
这个参数是决定风冷热泵正常使用的最关键参数，它是指风冷热泵的进风温度、进出水温度在设计工况下时其所具备的制冷量或制热量。它可从有关厂家提供的产品样本中查得。但在设计中也发现这样的情况，那就是有的厂商所提供的样本参数并未经过测试而是抄自其它厂家的相关样本。这给设计人员的正确选型带来了一定困难。因此笔者建议在有条件的情况下设计人员可根据有关厂家的风冷热泵所配置的压缩机型号，从压缩机生产厂家处获得该压缩机的变工况性能曲线，根据热泵的设计工况查得该压缩机在热泵设计工况下的制冷量和制热量，从而判断该样本所提供参数的真伪。 COP值 该值是确定风冷热泵性能好坏的重要参数，其值的高低直接影响到风冷热泵使用中的耗电量，因此，应尽量选择COP值高的机组。我国国家标准是COP值为2.57，多数进口或合资品牌的COP在3左右，个别进口品牌的高效型机组其值可达到3.8。 噪声 噪声也是衡量一台风冷热泵机组的重要参数，它直接关系到热泵运行时对周围环境的影响。国内有关专家曾根据工程实测对各类进口热泵的噪声划分为三档，第一档在85dB以上、第二档在75～85dB 之间、第三档在75dB以下。我们在进行工程设计选型中应优先选择噪声在80dB以下的机组。 外型尺寸 风冷热泵机组大多布置在室外屋顶，它在进行设备布置时对设备
风冷热泵机组概述 东盛环保公司提供 风冷热泵机组是由压缩机——换热器——节流器——吸热器——压缩机等装置构成的一个循环系统。冷媒在压缩机的作用下在系统内循环流动。它在压缩机内完成气态的升压升温过程（温度高达100℃），它进入换热器后与水进行热量交换，被冷却并转化为流液态，当它运行到吸热器后，液态迅速吸热蒸发再次转化为气态，同时温度下降至零下20℃——30℃，这时吸热器周边的空气就会源源不断地将低温热量传递给冷媒。冷媒不断地循环就实现了空气中的低温热量转变为高温热量并加热冷水过程。 一．特点 1.风冷热泵机组属中小型机组，适用于200-10000平方米的建筑物。 2.空调系统冷热源合一，更适用于同时具有采暖和制冷需求的用户，省去了锅炉房。 3.机组户外安装，省去了冷冻机房，节约了建筑投资。 4.风冷热泵机组的一次能源利用率可达90%，节约了能源消耗，大大降低了用户成本。 5.无须冷却塔，同时省去了冷却水泵和管路，减少了附加设备的投资。 6.风冷系统替代冷却水系统，更适用于缺水地区。 二．性能 冷热量 这个参数是决定风冷热泵正常使用的最关键参数，它是指风冷热泵的进风温度、进出水温度在设计工况下时其所具备的制冷量或制热量。它可从有关厂家提供的产品样本中查得。但在设计中也发现这样的情况，那就是有的厂商所提供的样本参数并未经过测试而是抄自其它厂家的相关样本。这给设计人员的正确选型带来了一定困难。因此笔者建议在有条件的情况下设计人员可根据有关厂家的风冷热泵所配置的压缩机型号，从压缩机生产厂家处获得该压缩机的变工况性能曲线，根据热泵的设计工况查得该压缩机在热泵设计工况下的制冷量和制热量，从而判断该样本所提供参数的真伪。 COP值 该值是确定风冷热泵性能好坏的重要参数，其值的高低直接影响到风冷热泵使用中的耗电量，因此，应尽量选择COP值高的机组。目前我国国家标准是COP值为2.57，多数进口或合资品牌的COP在3左右，个别进口品牌的高效型机组其值可达到3.8。 噪声 噪声也是衡量一台风冷热泵机组的重要参数，它直接关系到热泵运行时对周围环境的影响。国内有关专家曾根据工程实测对各类进口热泵的噪声划分为三档，第一档在85dB以上、第二档在75～85dB之间、第三档在75dB以下。我们在进行工程设计选型中应优先选择噪声在80dB以下的机组 系统 风冷热泵机组的系统分析，就是在风冷热泵的选型过程中除了比较各自的制冷量、制热量、COP值、噪声、运行重量、外形尺寸等参数外，还要对其各自的压缩机型式、冷凝器型式及布置、热力膨胀阀的配置、蒸发器型式、除霜方式、能量调节方式以及热泵系统的自控和安全保护等等加以分析，比较其各自在系统配置方面的优缺点。 三．压缩机的型式： 用于风冷热泵的压缩机型式主要有活塞式、涡旋式、螺杆式三种型式。根据热泵工作的特点是运行时间长、压缩比大等情况，笔者认为涡旋式和螺杆式压缩机将成为热泵压缩机的主流。其理由是： 1.涡旋式和螺杆式压缩机较活塞式压缩机具有传动件少，从而使压缩机的磨擦损耗相应减
热泵机组选型指南 热泵机组是一种新型节能的空调制冷装置。 热泵机组实质上是一种能源采掘机械，它以消耗一部分高质能(机械能、电能或高温热能等)为补偿，通过热力循环，把环境介质(水、空气、土地)中贮存的能量加以发掘进行利用。它的工作原理与制冷机相同，都按逆循环工作，所不同的是它们工作的温度范围和要求的效果不同。致冷装置是将低温物体的热量传给自然环境以造成低温环境，热泵则是从自然环境中吸取热量，并将它输送到人们所需要温度较高的物体中去。 热泵的特点：(1)它的突出优点就是热效率高。节能效果显著。这种装置只需耗费少量的高质能(电能、机械功)就可获得较多的热能．因而减少了能源的浪费。(2)热泵技术的采用可取代大量的锅炉房，节省燃料，减少大气的污染。余热得到利用的同时也减少了热污染，因而使城市环境卫生必然得到改善，也有利于生态平衡。 工作原理 在蒸发器中工质蒸发吸取自然水源或环境大气中的热能，经压缩后的工质在冷凝器中放出热量加热供热系统的回水，然后由循环泵送到热用户用作采暖或热水供应等。在冷凝器中，工质凝结成饱和液体，经节流降压降温进入蒸发器，蒸发吸热、气化为干饱和蒸气，从而完成一个循环。
基本组成 热泵机组主要由压缩机、冷凝器、蒸发器、节流装置、四通换向阀等组成热泵，另外还有必需的制冷空调、采暖的室内末端输配系统，包括加压送风系统或地板盘管、风机盘管等。 分类 按热源分：空气源、地下水源、土壤源、太阳能以及排放余热等。 按压缩机种类分：活塞式、螺杆式、涡旋式、离心式。 按热泵的功能分：单纯供热、交替制冷供热、同时制冷供热。 按驱动形式分：电力压缩式、热力吸收式。 按供热温度分：低温（<100℃）、高温（>100℃） 按热源和冷媒介质的组合方式分：空气－空气源热泵、空气－水源热泵、水－水源热泵、水－空气源热泵。 选型指南 1.热泵机组的冷负荷计算方法同于常规空调系统，热负荷计算方法于采暖系统大致相同，但需考虑新风耗热量。 2.选型时要注意当地是否有足够的水源（包括水量、水温及水质）、电源和热源（包括热源性质、品位高低）。
风冷热泵系统施工方案 1. 风冷热泵设备安装 1.1开箱检验。根据设备装箱清单说明书，合格证，检验记录和必要的装配图及其它技术文件，核对型号，规格以及全部零件、部件、附属材料和专用工具；主体和零件等的表面有没有缺损和锈蚀等情况；设备填充的保护气体有没有泄漏，油封是否完好，开箱检查后对设备采取保护措施，不宜过早或任意拆除包装，以免设备受损；设备的进出口应封闭完好，随机的零部件应齐全不缺损。 1.2在混凝土基础达到护养强度、表面平整、位置尺寸、标高、预留孔洞及预埋件等均符合设计要求后才可进行安装。 1.3制冷设备的搬运及吊装应符合下列规定：吊运前应该核对设备重量，吊运捆扎应该稳固，主要承力点应高于设备重点；吊装具有公共底座的机组，其承 水平度允许偏差均为0.5/1000。再调整好弹簧减震器，将减震器调节螺杆抹上黄油，做好配管前的准备工作且做好管口的保护工作，风冷式冷热水机组的进、
出水管连接位置正确，严密不漏。 2. 水泵的安装 2.1安装前检查泵叶轮是否有阻滞、卡涩现象，声音是否正常。 2.2水泵就位后进行找平找正。通过调整垫铁，使之符合下列要求：整体泵安装以进出口法兰面为基准进行找平，水平度允许偏差纵向0.05mm/m，横向为0.10mm/m；解体安装的泵以泵体加工面或进出口法兰面为基准，纵向、横向的水平度允许偏差为0.05mm/m。 2.3采用联轴器传动的泵，两轴的对中偏差及两半联轴器两端面间隙要符合泵的技术文件要求和施工及验收规范要求。 2.4与泵连接的接管设置单独的支架，进出口应设减振用的橡胶软接头。接管与水泵连接前，管路必须清洁；密封面和螺纹不能有损坏；相互连接的法兰端面或螺纹轴心必须平行、对中，不得借法兰螺栓或管接头强行连接。配管中要注意保护密封面，以保证连接处的气密性。 2.5有拆检及清洗要求的泵体，须对泵进行拆检并编号，用机油清洗后再按编号重新组装。 2.6水泵试车前，先拆除联轴器的螺栓，使电机与机械分离（不可拆除的或不需拆除的例外），盘车应灵活，无阻卡现象。检查完后，再重新连接联轴器并进行校对。打开泵进水阀门，点动电机。叶轮正常后再正式启动电动机，待泵出口压力稳定后，缓慢打开出口阀门调节流量。泵在额定负荷下运行4小时后，无异常现象为合格。 2.7管路与泵连接后，如在管路上进行焊接和气割，必须拆下管路或采取必要措施，防止焊渣进入泵内损坏水泵。 3. 风机盘管的安装 3.1风机盘管安装必须水平，以防冷凝水外溢。
风冷热泵机组 风冷热泵机组是由压缩机--换热器--节流器--吸热器--压缩机等装置构成的一个循环系统。冷媒在压缩机的作用下在系统内循环流动。它在压缩机内完成气态的升压升温过程（温度高达100℃），它进入换热器后释放出高温热量加热水，同时自己被冷却并转化为流液态，当它运行到吸热器后，液态迅速吸热蒸发再次转化为气态，同时温度下降至零下20℃ --30℃，这时吸热器周边的空气就会源源不断地将低温热量传递给冷媒。冷媒不断地循环就实现了空气中的低温热量转变为高温热量并加热冷水过程。 风冷热泵机组特点 1.风冷热泵机组属中小型机组，适用于200-10000 平方米的建筑物。 2.空调系统冷热源合一，更适用于同时采暖和制冷需求的用户，同时省去了锅炉房。 3.机组户外安装，省去了冷冻机房，节约了建筑投资。 4.风冷热泵机组的一次能源利用率可达90%，节约了能源消耗，大大降低了用户成本。 5.无须冷却塔，同时省去了冷却水泵和管路，减少了附加设备的投资。 6.无冷却水系统动力消耗，无冷却水损耗，更适用于缺水地区。风冷热泵机组性能分析冷热量这个参数是决定风冷热泵正常使用的最关键参数，它是指风冷热泵的进风温度、进出水温度在设计工况下时其所具备的制冷量或制热量。它可从有关厂家提供的产品样本中查得。但目前在设计中也发现这样的情况，那就是有的厂商所提供的样本参数并未经过测试而是抄自其它厂家的相关样本。这给设计人员的正确选型带来了一定困难。因此笔者建议在有条件的情况下设计人员可根据有关厂家的风冷热泵所配置的压缩机型号，从压缩机生产厂家处获得该压缩机的变工况性能曲线，根据热泵的设计工况查得该压缩机在热泵设计工况下的制冷量和制热量，从而判断该样本所提供参数的真伪。 COP值 该值是确定风冷热泵性能好坏的重要参数，其值的高低直接影响到风冷热泵使用中的耗电量，因此，应尽量选择COP值高的机组。目前我国国家标准是COP值为2.57，多数进口或合资品牌的COP 在3 左右，个别进口品牌的高效型机组其值可达到3.8。 噪声 噪声也是衡量一台风冷热泵机组的重要参数，它直接关系到热泵运行时对周围环境的影响。国内有关专家曾根据工程实测对各类进口热泵的噪声划分为三档，第一档在85dB 以上、第二档在75～85dB之间、第三档在75dB 以下。我们在进行工程设计选型中应优先选择噪声在80dB 以下的机组。 外型尺寸风冷热泵机组大多布置在室外屋顶，它在进行设备布置时对设备与周围墙面的间距、设备之间的间距都有明确要求，因此我们在进行设备选型时必须考虑所选设备尺寸是否符合设备布置的尺寸要求。在性能相同的前提下应优先选用尺寸较小的机组，以减小设备的占地面积。 运行重量 由于风冷热泵机组大多布置在屋面，因此在选型时必须考虑屋面的承重能力，必要时应 与结构专业协商，增强屋面的承重能力。但在设备选型时我们应优先选择运行重量较轻的机组。 风冷热泵机组系统分析 风冷热泵机组的系统分析，就是在风冷热泵的选型过程中除了比较各自的制冷量、制热
风冷热泵冷热水机组既可供冷又可供热，省却了锅炉房和冷却水系统，安装灵活方便。机组运行采用微电脑控制，可靠性较高。因此在长江流域的许多空调工程中得以广泛采用。但由于各地气候条件不同，再加上工程设计方面也缺少经验。因此在使用中也发现了不少问题。 在进行一个工程的设计过程中，如果当地气候环境允许，同时经过技术经济分析比较后确定该工程空调冷热源采用风冷热泵机组.选型的主要内容首先是机组的总体性能分析，它包括热泵机组的制冷量、制热量、COP值、噪声、外形尺寸、运行重量等参数。其次，分析该类热泵的内部配置，它包括压缩机型式、冷凝器结构及布置、热力膨胀阀的配置、蒸发器型式、能量调节方式、融霜方式、安全保护及自动控制项目等等。在进行上述分析比较后我们就可以选择一款较为理想的机组，接下来的工作就是进行设备布置，这过程中我们必须考虑设备之间的合理间距，辅助热源的配置以及多台热泵整体运行噪声对周围环境的影响等。。 风冷热泵的性能分析 风冷热泵的冷热量：它是指风冷热泵的进风温度、进出水温度在设计工况下时其所具备的制冷量或制热量。它可从有关厂家提供的产品样本中查得。但目前在设计中也发现这样的情况，那就是有的厂商所提供的样本参数并未经过测试而是抄自其它厂家的相关样本。这给设计人员的正确选型带来了一定困难。因此笔者建议在有条件的情况下设计人员可根据有关厂家的风冷热泵所配置的压缩机型号，从压缩机生产厂家处获得该压缩机的变工况性能曲线，根据热泵的设计工况查得该压缩机在热泵设计工况下的制冷量和制热量，从而判断该样本所提供参数的真伪。 风冷热泵的COP值：该值是确定风冷热泵性能好坏的重要参数，其值的高低直接影响到风冷热泵使用中的耗电量，因此，应尽量选择COP值高的机组。目前我国国家标准是COP值为2.57，多数进口或合资品牌的COP在3左右，个别进口品牌的高效型机组其值可达到3.8。 噪声：噪声也是衡量一台风冷热泵机组的重要参数，它直接关系到热泵运行时对周围环境的影响。国内有关专家曾根据工程实测对各类进口热泵的噪声划分为三档，第一档在85dB以上、第二档在75～85dB之间、第三档在75dB以下。我们在进行工程设计选型中应优先选择噪声在80dB以下的机组。 外型尺寸：风冷热泵机组大多布置在室外屋顶，它在进行设备布置时对设备与周围墙面的间距、设备之间的间距都有明确要求，因此我们在进行设备选型时必须考虑所选设备尺寸是否符合设备布置的尺寸要求。在性能相同的前提下应优先选用尺寸较小的机组，以减小设备的占地面积。 运行重量：由于风冷热泵机组大多布置在屋面，因此在选型时必须考虑屋面的承重能力，必要时应与结构专业协商，增强屋面的承重能力。但在设备选型时我们应优先选择运行重量较轻的机组。 风冷热泵的工程设计
投标邀请函 致： 1、（招标人）xxx办公楼风冷热泵模块式空调采购及安装工程，已具备招标条件，现对该工程的施工进行邀请招标择优选定承包人。 2、本次招标工程项目的概况如下： （1）招标工程项目的规模：建筑面积㎡，地下层，地上层 （2）招标范围：设计施工图纸范围内的全部工程 （3）工程建设施工地点：xxxxxx （4）计划开工日期为：年月 （5）工程质量要求达到国家施工验收规范合格标准。 3、被邀请参加本次招标项目投标的投标人均须具备国内品牌：美的、格力、海尔有效的销售代理授权证明，机电安装工程施工总承包二级及以上或机电设备安装工程专业承包三级及以上资质（允许联合投标），且具有足够的资产及能力来有效地履行合同的供应商 4、请你方在接到本投标邀请函后，到招标代理机构处获取招标文件及相关资料，时间为年月日时至年月日时。 5、有关本项目投标的其他事宜，详见招标文件；或与招标人联系。 招标人：xxxxxxxx公司 邮政编码：联系电话： 联系人： 日期：年月日
十堰市城市公交集团有限公司重庆路办公楼风冷热泵机模块空调 采购及安装 招 标 文 件 编制单位：xxxxxxxxx公司 时间：年月
第一章招标标书 一、工程概况 本工程为xxxx公司重庆路办公楼风冷热泵模块空调采购及安装工程，地下一层，地上九层建筑面积约：15305㎡。 二、室内外设计计算参数 室内空调设计参数： 三、总则 1、本技术规范提出的是最低限度的要求，并未对一切细节作出规定，也未充分引述有关标准和规范的条文，投标方应保证提供符合本技术规范和有关最新标准的产品，保证产品符合设计要求及本技术规范要求和最新标准。 2、在签订合同后，招标方保留对本技术协议书提出补充要求和修改的权利，投标方应承诺予以配合。如具体项目提出修改，由招标方、投标方双方商定。 3、本技术规范所使用的标准如与投标方所执行的标准发生矛盾时，按较高标准执行。 4、本技术规范经招标方、投标人双方签字认可后作为订货合同的附件，与合同正文具有同等法律效力。 四、主要设备技术要求 1．热泵机组（主机） 1）通用技术要求 a.风冷模块式热泵机组。 b.国内知名品牌：美的、格力、海尔。 c. 采用环保冷媒。 2）设备规范 a.设备达到的技术参数要求： 设计环境工作温度：机组设计环境工作温度制热为-10℃--21℃、制冷10℃--48℃。 机组能效比：制冷cop值不小于3.2。 b.投标人提供设备能达到的实际技术参数应满足要求，如投标人的技术 参数达不到要求的参数时，应填技术偏离表。 c.投标人提供设备选型及性能参数必须等于或优于招标文件要求。
风冷热泵冷热水机组的选型与工程设计(一) 摘要：本文阐述了风冷热泵冷热水机组选型中应注意的几方面问题，并对其在工程设计中的几个应注意事项谈了作者自己的体会。 关键字：风冷热泵；冷热水机组；COP噪声；冷凝器；蒸发器 风冷热泵冷热水机组是九十年代在我国开始应用的一种新型空调主机，此类机组既可供冷又可供热，省却了锅炉房和冷却水系统，安装灵活方便。机组运行采用微电脑控制，可靠性较高。因此在长江流域的许多空调工程中得以广泛采用。但由于各地气候条件不同，再加上工程设计方面也缺少经验。因此在使用中也发现了不少问题。本文作者根据自己近年来的工程经验谈几点体会，以供广大同行参考。 在进行一个工程的设计过程中，如果当地气候环境允许，同时经过技术经济分析比较后确定该工程空调冷热源采用风冷热泵机组，那么设计人员应该着手对国内外相关厂家的产品进行分析比较，为用户选择一款较为经济合理的热泵产品。选型的主要内容首先是机组的总体性能分析，它包括热泵机组的制冷量、制热量、COP值、噪声、外形尺寸、运行重量等参数。其次，分析该类热泵的内部配置，它包括压缩机型式、冷凝器结构及布置、热力膨胀阀的配置、蒸发器型式、能量调节方式、融霜方式、安全保护及自动控制项目等等。在进行上述分析比较后我们就可以选择一款较为理想的机组，接下来的工作就是进行设备布置，这过程中我们必须考虑设备之间的合理间距，辅助热源的配置以及多台热泵整体运行噪声对周围环境的影响等。下面就以上几方面的问题分别加以阐述。 风冷热泵的性能分析 风冷热泵的冷热量：这两个参数是决定风冷热泵正常使用的最关键参数，它是指风冷热泵的进风温度、进出水温度在设计工况下时其所具备的制冷量或制热量。它可从有关厂家提供的产品样本中查得。但目前在设计中也发现这样的情况，那就是有的厂商所提供的样本参数并未经过测试而是抄自其它厂家的相关样本。这给设计人员的正确选型带来了一定困难。因此笔者建议在有条件的情况下设计人员可根据有关厂家的风冷热泵所配置的压缩机型号，从压缩机生产厂家处获得该压缩机的变工况性能曲线，根据热泵的设计工况查得该压缩机在热泵设计工况下的制冷量和制热量，从而判断该样本所提供参数的真伪。 风冷热泵的COP值：该值是确定风冷热泵性能好坏的重要参数，其值的高低直接影响到风冷热泵使用中的耗电量，因此，应尽量选择COP值高的机组。目前我国国家标准是COP值为2.57，多数进口或合资品牌的COP在3左右，个别进口品牌的高效型机组其值可达到3.8. 噪声：噪声也是衡量一台风冷热泵机组的重要参数，它直接关系到热泵运行时对周围环境的影响。国内有关专家曾根据工程实测对各类进口热泵的噪声划分为三档，第一档在85dB以上、第二档在75～85dB之间、第三档在75dB以下。我们在进行工程设计选型中应优先选择噪声在80dB以下的机组。 外型尺寸：风冷热泵机组大多布置在室外屋顶，它在进行设备布置时对设备与周围墙面的间距、设备之间的间距都有明确要求，因此我们在进行设备选型时必须考虑所选设备尺寸是否符合设备布置的尺寸要求。在性能相同的前提下应优先选用尺寸较小的机组，以减小设备的占地面积。 运行重量：由于风冷热泵机组大多布置在屋面，因此在选型时必须考虑屋面的承重能力，必要时应与结构专业协商，增强屋面的承重能力。但在设备选型时我们应优先选择运行重量较轻的机组。 风冷热泵的系统分析 所谓风冷热泵的系统分析，就是在风冷热泵的选型过程中除了比较各自的制冷量、制热量、COP值、噪声、运行重量、外形尺寸等参数外，还要对其各自的压缩机型式、冷凝器型式及布置、热力膨胀阀的配置、蒸发器型式、除霜方式、能量调节方式以及热泵系统的自控和安
黑龙江建筑职业技术学院毕业设计 毕业题目：风冷热泵机组FRA60设计 学生： 指导教师： 专业：供热通风与空调工程技术 班级：供热班 2011年6月
黑龙江职业技术学院毕业设计评审意见表毕业设计题目风冷热泵机组FRA60设计 学生姓名专业班级 指导教师评语: 建议成绩： 指导教师（签字）： 年月日
答辩委员会意见: 答辩委员会(教师姓名、职称)：毕业设计成绩：
风冷热泵机组FRA60设计 摘要 风冷热泵冷热水机组是九十年代在我国开始应用的一种新型空调主机，此类机组既可供冷又可供热，省却了锅炉房和冷却水系统，安装灵活方便，系统简单不占用机房，可放置楼顶，同时还可满足热水需求。机组运行采用微电脑控制，可靠性较高。因此在许多空调工程中得以广泛采用。 本文就风冷热泵中央空调的性能、系统、工程设计做以分析，并告诉我们设计一台风冷热泵机组该如何选择压缩机、蒸发器、冷凝器、热力膨胀阀及各类辅助设备，通过上述设备工作所能达到的制冷量、制热量、COP值等。由此使我们知道了设计时应该注意的问题，了解绿色建筑与中央空调的关系，以此得出中央空调系统具有节能、运用可靠、应用灵活方便等优点，适宜某些建筑，如多居室、别墅、办公室、娱乐场所、大型商场等地方使用使用。 关键词：风冷热泵；冷热水机组；压缩机；蒸发器；冷凝器；热力膨胀阀；COP值
目录 摘要 1 绪论1 2 风冷热泵机组的性能分析 2 2.1风冷热泵的冷热量 2 2.2风冷热泵的COP值 2 2.3外型尺寸2 2.4噪声 2 2.5运行重量 2 3 风冷热泵的系统分析 3 3.1压缩机的型式 3 3.2冷凝器的型式与布置 3 3.3热力膨胀阀配置 3 3.4蒸发器型式 4 3.5轴流风机的配置 4 3.6能量调节方式 4 3.7除霜方式 4 3.8安全保护与控制 5 3.8.1风冷热泵的安全保护系统 5 3.8.2风冷热泵控制 5 4 风冷热泵的工程设计 6 4.1风冷热泵的布置 6 4.2辅助热源的配置 6 4.3工程的噪声控制 6 5 风冷热泵机组FRA60设计计算 7 5.1制冷循环参数与热力计算 7 5.1.1各点参数值 7 5.2.2热力计算 7 6 压缩机的选型与蒸发器的设计计算 8 6.1压缩机的选型 8 6.2蒸发器的设计计算 8 7 冷凝器的设计计算9 7.1冷凝器热负荷 9 7.2冷凝器结构的初步确定 9 7.3几何参数计算 9 7.4冷凝器进口空气状态参数 9 7.5风量及风机的选择 9 7.6冷凝器的传热面积与外形尺寸 9
必须采用同一品牌全部投标 以上设备的制造、运至施工现场、配合土建安装施工单位指导安装、试验、调试及试运行、人员培训、验收等所有内容。 二、技术要求： （一）风冷涡旋式机组 1、设备型式：风冷涡旋热泵机组 2、数量：1套（最多不超过3台） ( 如投标产品为节能机型，必须列入2009国家第六批节能目录，并提供其目录表及认证中心证件，在评标时，并提供按其报价下浮2%计算投标价格，不是节能产品按原报价计算) 3、额定制冷量：≥370kW 额定制热量：≥373kw 投标方也可根据所投产品，在台数和单台制冷量上作调整，但总冷量不允许有负偏差，并能满足现场安装条件。 4、制冷剂：R22或R407C及更新的环保制冷剂 5、能效比COP（整机，含风扇）：≥2.7 备注：上述制冷量及COP值均为在下述冷冻水温及室外环境温度下测量 6、冷冻水供回水温度：7/12 ℃ 7、热水供回水温度：45/40℃ 8、制冷室外环境温度：35℃ 9、制热室外环境温度：干球7℃/湿球6℃ 10、电源：AC 380V 要求电压在额定值的±10% 波动内机组应确保正常启动和运行。 11、噪音：低于国家规定要求（投标文件中填写具体数据，并与检测报告中的数值一致。） 12、控制、保护显示功能：要求采用微电脑控制系统 控制功能要求达到： （1）工作模式切换 （2）智能除霜 （3）智能控制开启系统数量 （4）系统安全保护 （5）机组故障自诊 （6）均衡运行 （7）现场、远距离开停机 （8）冬天自动防冻结运行 （9）各模块分时启动 （10）水泵启停控制 保护功能要求达到： （1）压缩机高低压保护 （2）相序保护 （3）过流保护 （4）机组放冻结保护 （5）机组防过热保护 （6）频繁启停保护 （7）水流开关保护