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Review on CO2 heat pump water heater for residential use in Japan
Article in Renewable and Sustainable Energy Reviews · June 2015
DOI: 10.1016/j.rser.2015.05.083
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Review on CO2heat pump water heater for residential use in Japan
Jian-Fei Zhang a,Yan Qin b,Chi-Chuan Wang c,n
a Compressor Technology Department,Panasonic Appliances Compressor(Dalian)Co.,Ltd.,Dalian116033,Liaoning,PR China
b R&D Center,Panasoni
c Appliances Compressor(Dalian)Co.,Ltd.,Dalian116033,Liaoning,PR China
c Department of Mechanical Engineering,National Chiao Tung University,Hsinchu300,Taiwan
a r t i c l e i n f o
Article history:
Received15November2013
Received in revised form
3May2015
Accepted26May2015
Keywords:
Carbon dioxide
Heat pump water heater
Compressor
Water–CO2gas cooler
a b s t r a c t
The present study presents an overview of CO2heat pump water heater for residential use in Japan.The
contents include the general background,current market,and the technology evolvement of the
transcritical CO2system,especially on the key components like compressor and gas cooler.Some
cutting edge technology associated with the high ef?cient compressors and its integration with
expander,such as swing compressor,sub-compressor,two-stage compressor,scroll expander,and
dual-sided scroll-type expander are elaborated in this review.Some ingenious tube designs to promote
the performance of gas cooler are also studied.In practice,the dominant thermal resistance may occur in
the CO2side or water side,thereby implementing twisted tube or dimple tubes may be quite effective.
The placement of enhancement on the water side is especially effective when the operational pressure is
close to the critical pressure whereas heat transfer enhancement is more helpful if the operational
pressure is comparatively high.For augmentation on the CO2side,it would be more bene?cial to place
enhancement a distance away from the pseudo-critical region.
&2015Elsevier Ltd.All rights reserved. Contents
1.Introduction (1383)
1.1.Current market size in Japan (1384)
1.2.Main manufacturers (1384)
1.3.Product trends (1385)
https://www.doczj.com/doc/551772548.html,pressor (1385)
2.1.Current status of the compressors (1385)
2.1.1.Rotary compressor (1385)
2.1.2.Swing compressor (1386)
2.1.3.Scroll compressor (1386)
2.2.Future trends (1386)
2.2.1.Two-stage compressor (1386)
2.2.2.Expander and expander–compressor (1387)
3.Water–CO2heat exchanger (1388)
4.Other heat pump water heater standard for the major countries (1390)
5.Conclusions (1390)
Acknowledgments (1391)
References (1391)
1.Introduction
In Japan,energy demand for hot tap water accounts for about
30%of the total residential energy consumption,but most of this
demand(over90%)is produced by direct combustion of fossil
fuel which may lead to pollution concerns and environmental
Contents lists available at ScienceDirect
journal homepage:https://www.doczj.com/doc/551772548.html,/locate/rser
Renewable and Sustainable Energy Reviews
https://www.doczj.com/doc/551772548.html,/10.1016/j.rser.2015.05.083
1364-0321/&2015Elsevier Ltd.All rights
reserved.
n Correspondence to:EE474,1001University Road,Hsinchu300,Taiwan Depart-
ment of Mechanical Engineering,National Chiao Tung University,Hsinchu300,
Taiwan.
E-mail address:ccwang@https://www.doczj.com/doc/551772548.html,.tw(C.-C.Wang).
Renewable and Sustainable Energy Reviews50(2015)1383–1391
problems.Hence the development of high-performance heat pump water heaters using natural working ?uids had received a lot attention recently as far as energy conservation and green-house gas reduction is concerned [1].Among the existing natural refrigerants,carbon dioxide (CO 2)is especially prominent for its outstanding features like non ?ammable,nontoxic,no known carcinogenic,and free from mutagenic.Moreover,using CO 2in refrigerating systems can be regarded as an alternative form of carbon capture,thereby helping to relief the in ?uence on climate change [2].For the revival of CO 2refrigeration system,the pioneering works of Lorentzen et al.[3–5]had proved that the use of CO 2can meet the simultaneous needs for an ef ?cient air-conditioning and for hot water production.This can be made available by operating the CO 2system in the transcritical region [6].As a consequence,heat pump water heater systems using CO 2as a refrigerant had received a lot of efforts for the past several decades,e.g.[7–13].Numerous heat pump water heaters for the residential sector had been developed in recent years,and gradu-ally gained its popularity in Japan,hence the electrical utilities and the associated water heater manufacturers had granted the name
“Eco Cute ”to the heat pump water heaters that use natural refrigerant CO 2[14].
1.1.Current market size in Japan
Since the advent of Eco Cute products in 2001as the innovative heat pump technology capable of reducing the energy for heating water,the Eco Cute market has continued to grow.In 2011,the cumulative number of the installed units surpassed 3million,and the product has steadily penetrated into the housing market.As shown in Fig.1,with some 560,000units sold at its peak in 2010,the market size decreased moderately in 2011and 2012.In 2012,it is estimated at about 440,000units.The main reason for expecting the market to recover in 2013lies in a likely increase in the number of new housing constructions with respect to the rise of consumption tax which will be in effect at April 2014.Moreover,Eco Cute also accompanies with some special features during an emergency,such as its ability to supply hot water even during a power outage period [15].1.2.Main manufacturers
Denso is the ?rst CO 2heat pump water heater supplier on the market.Since then many Japanese manufacturers had set up the production line for Eco Cute product,including the major players such as Sanyo,Panasonic,Daikin,Hitachi,Mitsubishi Electric,Sanden,Corona,Toshiba Carrier and Matsushita Electric.The Eco Cute is mainly for residential use with a variety of models,ranging from single family homes and condominiums to those serving not only mild and cold climates,but also regions where it is necessary to withstand corrosion from salt spray.There are also multi-function Eco Cute models that can be combined with ?oor heating or a bathroom heater with a humidi ?er function.The unit capacity and water tank volume normally falls in the range of 4.5/6kW
and
Fig.1.Market size of Eco-cute units in
Japan.
Fig.2.Schematic for a typical residential Eco-cute unit.
J.-F.Zhang et al./Renewable and Sustainable Energy Reviews 50(2015)1383–1391
1384
370/460L,respectively,for residential use as seen in Fig.2.The corresponding speci?cation is tabulated in Table1(4.5kW capa-city,370L water tank,hot water supply model).
1.3.Product trends
Many Japanese manufacturers are striving to improve the overall energy ef?ciency of Eco Cute system by enhancing the performance of key components such as compressor and heat exchanger.The related technologies to tailor this problem are described in more details in the https://www.doczj.com/doc/551772548.html,pressor
At a very low critical temperature,the CO2transcritical cycles normally operate at a very high pressure level which is normally much higher than its counterpart refrigerants like R-410A or R-134a.The appreciably high pressure for CO2system requires special treatments of the key components,especially for the compressors.A detailed general comparison of CO2and R-410A/ R-134a compressor is shown in Table2
2.1.Current status of the compressors
As shown in Fig.3,rotary,swing and scroll are the three main types of compressors applicable to the current CO2water heat pump.The corresponding speci?cations from different manufacturers are tabu-lated in Table3.The typical displacement for the CO2compressors ranges from3.3to4.5cm3[17–20]with revolutions being1800–7200minà1[21]mostly.Typical rating condition may be designed at 4–4.5MPa for the suction pressure,9–10MPa for the discharge pressure and221C for the outlet temperature of the gas cooler.
2.1.1.Rotary compressor
Rotary compressor had been used in the traditional air con-ditioning and heat pump water heater system for a long time,and accordingly it was adopted for CO2refrigerant after certain modi?cations.Hideaki and Shinichi[18]improved the conven-tional R-410A refrigerant compressor using some newly developed technologies,such as the?exible structure for the cylinder vane slot and vane coating method.As a result,the developed CO2 compressor reveals a suf?ciently high performance,good oil circulation and reliability.Hideto and Naotaka[22]developed a single rotary compressor,featuring a so-called DLC-Si technology to reduce wear of the vane.They demonstrated that the wear at the vane with DLC-Si coating is at least two times slower than that with nitrided vane.Yokoyama et al.[23]performed a CFD simula-tion to improve the oil separation and to reduce the shell size inside the CO2rotary compressor using two measures,including ?attening a lower weight of the rotor and to set up a rotating discover a protruding balance weight.Okuda et al.[24]developed
Table1
Basic speci?cations for Eco cute.
Components Data S-
company P-
Company
D-
Company
H-
Company
M-
Company
Outdoor
unit Catalog
year
20092013201220122012
Capacity
(kW)
4.5
Power
(kW)
0.9150.980.9450.970.96
COP 4.9 4.6 4.8 4.6 4.7 CO2
Weight
(kg)
0.860.590.910.82
Unit
weight
(kg)
6143555549
Sound
(dB)
3838383838 Design
pressure
(MPa)
14/814/913.7/9.513.3/814/8.5
Water tank Volume
(L)
370
Weight
(kg)
7061675465
Test condition:dry/wet bubble temperature?16/121C,inlet/outlet water temperature?17/651C([16]).
Table2
Basic speci?cations for compressor in different refrigerants.
Refrigerant CO2R410A R134a
Global warming potential[2]120001300 Volume capacity ratio310.45 Design pressure(MPa)14\8 4.5\2.5 2.5\1.1 High side\low side
Max pressure difference(ratio)10 3.5 2.5Table3
Basic speci?cations for CO2compressors in Japan.
Manufacture Sanyo Mitsubishi E Daikin Denso
Reference[17][18][19][20] Compressor type Two-stage rotary Single rotary Swing Scroll Motor type DC motor
Size(mm)?118?217––?137?285 Displacement(cm3)1st stage:3.33
2nd stage:2.33 4.5 4.2
3.3
Fig.3.Schematic of the compressor layout for various companies.
J.-F.Zhang et al./Renewable and Sustainable Energy Reviews50(2015)1383–13911385
a high ef ?ciency rotary compressor based on inverter design for their ECO CUTE production.
2.1.2.Swing compressor
Owing to the high differential pressure of the CO 2rotary compressor,the internal gas leakage across the vane from the high to low pressure areas increases,leading to a degradation of compressor ef ?ciency.Therefore,Masahide et al.[19]developed a swing compressor which combined a vane and roller together as shown in Fig.4.With the help of swing compressor design,sliding between the vane and roller is eliminated and the wear problem is removed.As a consequence,the gas leakage problem is signi ?-cantly relieved.They therefore concluded that the swing com-pressor is more suitable for the CO 2refrigerant.
2.1.
3.Scroll compressor
Sakakibara et al.[20]developed the ?rst CO 2scroll compressor applicable for CO 2heat pump water heater.The unit worked very effectively since it can reduce as much as 30%energy consumption as compared to the gas combustion system from the level of electrical power generation,yet it also showed a 50%reduction of CO 2emission as compared to the gas combustion system.Based on a mass-production R-410A scroll compressor,Shimoji and Naka-mura [25]developed a prototype of a 10hp CO 2scroll compressor.They also provided a quantitative loss analysis of this compressor using a simpli ?ed model from the basic test,and the results showed that the test results were in line with the analysis.2.2.Future trends
Compressor technology for the CO 2transcritical systems has reached an advanced level after years of development.Recently,researchers are focusing on the two-stage compression and expander technology to boost the compressor ef ?ciency even higher [15].
2.2.1.Two-stage compressor
The pressure difference between discharge-and suction-pressure of CO 2refrigerant is several times larger than that of the conventional HFC (hydro ?uorocarbons)refrigerants.This brings about an increase of gas leakage and mechanical losses.However,by introducing the two-stage compression the pressure difference in each stage is considerably reduced,thereby higher system ef ?ciency and higher reliability can be obtained.Sato et al.[26]compared the compressor performances between single-stage and two-stage compression based on structure difference as depicted in Table 4.From the elaborate comparisons,it appears that the two-stage compression outperforms that of single-stage compression in every aspect.
Suzai et al.[27],Tadano et al.[28],and Yamasaki et al.[29]developed a two-stage rotary compressor as shown in Fig.5to ease the in ?uence of high pressure difference inherited with CO 2.By dividing the compression process into two separate compres-sions,the leakage at the seal is reduced so that high compression ef ?ciency can be attained.In addition,two pistons were placed out of phase (180deg.).With this opposite-side arrangement,the problems of vibration and noise are considerably reduced.From the fundamental CO 2properties,the high volumetric ef ?ciency with small piston size can be achieved.Yet smooth shaft rotation at start up and operation can be made available due to smaller rotational inertia and torque balance for the CO 2.In addition,the internal intermediate pressure design enabled the shell wall thickness to be 35%thinner than that of the high pressure operation.Accordingly this helps to reduce the total weight which is found to be about the same as the conventional R-410A compressor.Moreover,the internal intermediate pressure design makes the pressure difference between on and off period smaller than that of the 1-stage design.This eventually raises high reliability to prevent fatigue of the shell material through periodi-cally high/low pressures cycle.
Moreover,the two-stage compressor is suitable for economizer cycle,Kobayashi [17]implemented a CO 2heat pump and water heater system with an economic cycle for cold climate region using the compressor shown in Fig.5.Through this design,some 8kW heating capacity and the 4.5kW water heating performance at an outdoor air temperature of à201C were achieved,the capacity and COP is increased as much as 17%when compared to that with no economizer cycle.
Yokoyama et al.[30]developed a two-stage rotary compressor for CO 2heat pump systems with refrigerant injection.Fig.6shows the performance at various rotational speeds in association with the single-stage type having the same speci ?cations.They found that the compressor ef ?ciency of the two-stage type is superior to the single-stage type in the low rotational speed or high pressure-ratio.
Table 4
Comparison of compressor performance according to structure.Number of compression stages Shell pressure
Compression mechanism Shell thickness Gas injection Reliability Ef ?ciency
First stage Second stage
First stage Second stage First stage Second stage
Single stage Discharge pressure ààSuction pressure tàTwo stages
Discharge pressure
àta Intermediate pressure Scroll
Scroll ttttb tb tttScroll Rotary tttttàttRotary Scroll tttttttttttRotary
Rotary tttttàtttSuction pressure Scroll
Scroll tta tb tb tttScroll Rotary tta ttàttRotary Scroll tta àttttttRotary
Rotary
t
ta
ààttt
a Connection piping between ?rst and second stages is required.b
An oil pump must be placed in the middle of the
shaft.
Fig.4.Rotary compressor vs.swing compressor —a schematic.
J.-F.Zhang et al./Renewable and Sustainable Energy Reviews 50(2015)1383–1391
1386
Apparently,this is associated with the inherited lower compression ratio for each stage of the two-phase compression,thereby leading to a much lower gas leaking during compression.The two-stage type is also superior to the single-stage type in compressor ef?ciency and heating capacity because it has the ability to improve these performances with refrigerant injection during high pressure-ratio operation.
Sato et al.[26]developed a novel compressor for commercial CO2 heat-pump water heaters as shown in Fig.7.The developed com-pressor employs rotary and scroll mechanisms in the?rst and second stage respectively to minimize the leakage and mechanical losses.In addition,by employing an intermediate gas injection,the new compressor has attained a high heating capacity and a high ef?ciency under a wide range of conditions.Their test results showed a15% improvement at the rated condition and more than30%improvement emerges at a higher pressure ratio condition which is conversed to the conventional prototype single-stage scroll compressor.
2.2.2.Expander and expander–compressor
One of the major challenges with CO2in air-conditioning applications is the low system energy ef?ciency at higher operat-ing heat sink temperatures.The major loss in CO2cycles is the throttling loss associated with the expansion process.The avail-ability lost during the expansion process can be recovered with a work-producing expansion device,so called an expander[31].Ma et al.[32]calculated and compared the system performance using CO2and R-134a as the working?uids.Their results showed that the performance of CO2system can be improved by using a low cost displacement expander.The expander is easily connected to the compressor coaxially,which contributes to the improvement of recovery work.Their highest ef?ciency recovery ratio can reach up to14.5%of the input power of compressor.
Matsui et al.[33]developed a two-stage rotary expander (Fig.8)which has been designed to connect its shaft to the shaft of a commercial scroll compressor,and is designed to provide an expansion chamber surrounded by the piston and the cylinder in the second stage which is larger than that in the?rst stage.After examining the impact of each design parameter on the perfor-mance through the simulation,an optimized design had
been https://www.doczj.com/doc/551772548.html,parison of the two-stage and single-stage CO2compressors at P d/P s?2.53,taken from[30]
.
Fig.7.Two-stage compressor employs rotary and scroll mechanisms in the?rst and second stage[26]
.
Fig.5.Schematic for a hermetic two-stage CO2compressor.
J.-F.Zhang et al./Renewable and Sustainable Energy Reviews50(2015)1383–13911387
devised and the expander ef ?ciency is increased as much as 60%which is equivalent to a 6%rise of system COP.Hiwata et al.[34]designed a scroll pro ?le of the scroll expander applicable for CO 2refrigerant.Their design makes use of overexpansion and to control the axial force on the thrust bearing.Through this design,they had demonstrated an exceptionally high volumetric ef ?-ciency of 96%.
As shown in Fig.9,Kohsokabe et al.[35]developed a prototype of a scroll expander for CO 2refrigeration cycles.The test results show that their scroll expander revealed a maximum isentropic ef ?ciency of 70%.
In Fig.10,Nagata et al.[36]designed a dual-sided scroll-type expander and is combined with a sub-compressor.The associated installation and operation of this design is schematically shown in Fig.11.According to the experimental results of the prototype device,the sub-compressor increased the pressure by 1.30MPa,while the pressure drop between the inlet and outlet of the expander was 3.19MPa.They also demonstrated that the power consumption of the main-compressor can be reduced using the prototype of an expander originally designed for a CO 2refrigera-tion cycle with an intercooler.
3.Water –CO 2heat exchanger
There are two important challenges for water –CO 2heat exchanger applicable for the heat pump water heater.The ?rst is to provide a reliable leak detection of the heat exchanger during operation.The second is that the heat exchanger must withstand high pressures —at least 13MPa in the CO 2side.As far as a product is concerned,low cost,compact,and high ef ?ciency must also be taken into account.Apparently,the concerns are often against the challenges.
Taira [37]compared three types of the water –CO 2heat exchangers (double tube,smooth tube and dimple tube)as shown in Fig.12.The ?rst type is the double tube heat exchanger with leakage detection ditch,this leakage detectable tube was manu-factured from the insertion of another tube in the inner groove tube and was put together later on.However,the double tube design has the drawbacks of being heavy,expensive,and dif ?culty in reducing size because the bending ratio cannot be reduced.He then developed a new type (smooth tube)heat exchanger which combined water tube and CO 2tube with a counter ?ow con ?g-uration.The weight and volume of the new heat exchanger is about 10to 30%lower than those of a double-tube exchanger.Taira [37]further improved the water –CO 2heat exchanger using a dimple tube as appeared in Fig.12.Note that the superimposed dimple/cavity structure onto the surface structure reinforces the heat transfer augmentations as demonstrated by Wang et al.[38].This is because near wall vortices is generated in the cavity structure in fully developed ?ow region which augments heat transfer considerably.The design is especially useful when the thermal resistance is on the water side.In practice,the dominant thermal resistance is primarily on the water side as depicted by Yu et al.[39]and Lin.et al.[40].Note that it is often quite imperative to place enhancement in the dominant resistance side.For CO 2transcritical cycle,it is evitable that the CO 2will pass through
the
Fig.9.A prototype of a scroll expander for CO 2refrigeration cycles (Kohsokabe et al.[35]
).
Fig.10.A dual-sided scroll-type expander and is combined with a sub-compressor (Nagata et al.[36]
).
Fig.11.Schematic of the operation of a dual-sided scroll-type expander and is combined with a sub-compressor (Nagata et al.[36]
).
Fig.8.Schematic of the developed a two-stage rotary expander (from Matsui et al.[33]).
J.-F.Zhang et al./Renewable and Sustainable Energy Reviews 50(2015)1383–1391
1388
pseudo-critical point where property like heat capacity may show a surge rise,thereby leading to a signi ?cant rise of heat transfer coef ?cient,hence the major thermal resistance may occur in the water side.Notice that the surges of heat capacity and heat transfer coef ?cient at the pseudo-critical point become even pronounced if the system pressures are close the critical pressure.This phenomenon had been elaborated in some previous studies [39–41].However,it should be mentioned that if the operational pressure of CO 2is suf ?ciently high,say 10or 12MPa,the surge of heat capacity near the pseudo-critical point is rather small and the thermal resistance may switched from water side to CO 2side.In this regard,the enhancement can be simply placed at the front or rear part of the gas cooler for effective reduction of total thermal resistance and for lowering the pressure drop.Okada [42]introduced a newly developed “twist &spiral gas cooler ”as depicted in Fig.13.The heat exchanger features a twisted pipe with three lines of spiral grooves for a water pipe,which are prepared by a twisting method.A refrigerant pipe (thin pipe)is wound around the twisted pipe and connected to each other by zinc-free soldering.This arrangement increases the contact surfaces on both pipes,thus increasing the heat transfer area,and the continuous spiral grooves in the twisted pipe accentuates the turbulence effect in the water and is also bene-?cial in reducing pressure loss in the heat exchanger.Furthermore,three pipes are wound around the three spiral grooves in parallel to reduce the pressure loss in the refrigerant.Sakakibara et al.[20]developed a capillary tube heat exchanger as shown in Fig.14,their calculation showed that the set mode of the water tube
and
Fig.12.Typical water –CO 2heat exchangers used in tube-in-tube type heat exchangers (double tube,smooth tube and dimple tube;Taira [37]
).
Fig.13.Con ?guration of “Twist &spiral developed by Okada [42]
.
Fig.14.Developed a capillary tube heat exchanger developed by Sakakibara et al.[20].
J.-F.Zhang et al./Renewable and Sustainable Energy Reviews 50(2015)1383–13911389
the CO 2tube inner diameter were the most important factors affecting the ef ?ciency.Andou et al.[43]focused on the tube in tube heat exchanger (Fig.15).In their test clearly revealed that the thermal resistance of water side is much higher than that of the CO 2side,therefore by use of the design of dimple heat exchanger,the water side heat transfer coef ?cient can be improved more than twice and accordingly a better overall heat transfer performance of the gas cooler is observed.
4.Other heat pump water heater standard for the major countries
Table 5depicts comparisons between the basic standards [16,44–46]applicable for heat pump water heater in major countries (Japan,EU,USA,and China).The JIS standard is generally associated with CO 2whereas other standards for the major countries are primarily for R-22/R-410A/R-134a.Hence cost ratio,evaluated relative to China,is generally highest for the CO 2system and a higher water temperature can be achieved for the CO 2heat pump.5.Conclusions
CO 2is a potential substitute for HFC refrigerants with favorable environmental properties when compared to other HFC
alternatives.In this paper,the CO 2heat pump water heater for residential use in Japan has been reviewed,especially for the technologies associated with the compressor and the water –CO 2heat exchanger.Currently rotary,swing and scroll are the three main types of compressors applicable to the current CO 2water heat pump.With typical displacement of the CO 2compressors ranging from 3.3to 4.5cm 3and with revolutions being 1800–7200min à1,the typical rating condition for the CO 2water heaters are designed at 4–4.5MPa for the suction pressure,9–10MPa for the discharge pressure and 221C for the outlet temperature of the gas cooler.For improving the high throttling loss from the high pressure-difference of CO 2,two-stage compressor and expander technology are proved to be quite effective to resolve this problem.In the meantime,normally the thermal resistance can be either at the water side or CO 2side,hence it is essential to improve the heat transfer coef ?cient of the water side or CO 2.Normally the surge of heat transfer performance of CO 2becomes more and more pro-nounced when the operational pressure is close to the critical point,leading to a dramatic rise of heat transfer coef ?cient and the dominant resistance may be on the water side.On the contrary,if the operational pressure is high,say over 10MPa,the detrimental thermal resistance may be switched to CO 2side.As a consequence,it is imperative to understand the thermal resistance distribution before employing the effective augmentation to the gas cooler tube.For practical application,the operational pressure is normally below 10MPa,hence current technology has introduced the
twisted
Fig.15.Various tube-in-tube heat exchanger developed by Andou et al.[43].
Table 5
Basic speci ?cations for heat pump water heater in different countries.Country Japan EU
USA China
Standard
JIS C-9220EN 16147AHRI 1301GB/T 23137[16][44]
[45][46]
Refrigerants
CO 2
R410A \R134a R22\R410A \R134a Hot water temperature 65à9055à65Ef ?ciency (COP) 4.6à4.9–
–
3.7à
4.6Cost ratio
3à4
1.5à2
$1
(relative to China)
J.-F.Zhang et al./Renewable and Sustainable Energy Reviews 50(2015)1383–1391
1390
design and dimple tubes to reduce the thermal resistance on the water side.
Acknowledgments
The last author,Dr.Chi-Chuan Wang,would like to thank for the support from the Ministry of Science and Technology of Taiwan,under contract104-3113-E-009-004.
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公司节约成本的具体方 案 文件排版存档编号：[UYTR-OUPT28-KBNTL98-UYNN208]
关于公司节约成本的具体方案 作为一个自主经营，自负盈亏的企业来讲，不光要潜心研究怎么挣钱如何创造效益，更要考虑如何节约成本，降低损耗。俗话说：“不省不成家”，企业就是一个大家庭，只有这个“大家”发展了，们各自的“小家”才会殷实，也就是印证了“大河有水小河满，大河无水小河干”的这句话。 最初我理解的公司节约，只考虑到了节约水电等能源方面的节约，缺忽视了还有其他很多方面。针对集团公司目前的状况，从三个方面着手精简公司成本。一.集团公司的能源节约。主要为节电 电的使用主要集中在照明设备电灯、电脑饮水机、和空调三个方面 水的成本主要在饮用水上面。公司的饮用水分为两种，分别是饮水机上大桶升的桶装水和农夫4升桶装水。其中大桶装水升，每桶10元，农夫桶装水每桶4升，每桶7元。 尽量做到以下几方面： 1.白天上班时间除非室内采光不足，否则不开启室内照明灯。 2.人走关灯，人来开灯，外出办公超过半小时离开时需关闭电灯，电脑。否则 一经发现罚款10元 3.空调恒定开在26度，关机后须断电。对于下班没关电脑（包括显示器）的员 工，罚款10元，以示批评。
水的成本主要在饮用水上面。公司的饮用水分为两种，分别是饮水机上大桶18升的桶装水和农夫4升桶装水。其中大桶装水升，每桶10元，农夫桶装水每桶4升，每桶7元。 目前情况下，每周平均使用7桶大桶装水和40桶农夫纯净水。如果提高大桶纯净水的使用量而降低农夫桶装水，则是一笔可观的费用。 二．集团公司的办公费节约。 由财务部财务总监计算出当月办公费使用的大体金额，主要包括纸张、墨盒、一次性口杯、易损耗的其他办公用品。立足当月，参照前几月，做出下月的办公费预算，月底检查完成情况，如果超支了，则要找出超支的重点，从源头上控制浪费。 纸张双面打印提倡了很多年，但我发现很少时候能做到。我觉得问题的关键不是大家不知道双面打印节省纸张，而在于很少人能在打印的时候把用过的纸放进打印机里。没有人做这个动作，那打出来的东西就只能是单面的、一次性的。解决这个问题，可以出台规定，除了公司重要文件不允许直接使用白纸打印。另外将打印过的纸张放到打印机放的显眼地方，方便看到使用。（这个动作我已经做了） 即使双面打印的纸张在不是完全看不清的情况下仍旧可以留下来当草稿纸。 在采购的时候同时采购相应的内件产品，中性笔、圆珠笔的笔芯，活页本的内页。都可以增加办公用品的使用寿命。
八年级（下）复习之语法归纳与练习 Unit 1 语法一：动词不定式作宾语语法二：动词不定式作宾语补足语 语法三：动词不定式作目的状语 【练一练】．单项选择。 ( ) 1. Our teacher gave us 10 minutes __________ about the question. A. thinks B. to think C. thinking D. thought ( ) 2. My father decided ________smoking. A. giving up B. to give up C. give up D. to giving up ( ) 3. You may take a horse to the river, but you can't make it________. A. to drink B. drank C. drink D. drinking ( ) 4. I didn't ask him ______to my party, but he came. A. to come B. come C. came D. coming ( ) 5. You can use a tool ________ a fire. A. make B. making C. to make D. to making Unit 2 语法一：动名词作主语语法二：动名词作宾语 【练一练】I．单项选择。 ( ) 1. __________ the train means waiting for another hour. A. Miss B. Missed C. Missing D. To missing ( ) 2. After _______his homework he went on to write a letter to his parents. A. finishes B. finishing C. finished D. to finish ( ) 3. _________ may cause cancer. A. Smoking B. Smoked C. Smoke D. To smoking ( ) 4. As she is looking forward to __________ from me, please remember to send this letter to her as soon as possible. A. hear B. hearing C. heard D. be heard ( ) 5. Grandma said that she had a lot of trouble __________ your handwriting. A. to read B. read C. reading D. to reading ( ) 6. Writing stories and articles __________ what I enjoy most. A. is B. are C. was D. were II．用括号内所给动词的适当形式填空。 7. He came to the party without ________ (invite). 8. It took the workmen only two hours to finish ________ (repair) my car. 9. ________ (keep) your room clean is a way to stay away from disease. 10. He is very busy _______ (do) his homework. 11. Please stop _______ (talk), boys. I have something important to tell you. 12. Before ______ (buy) the house, you should get somebody to look it over. 13. ________ (sh ake) hands is a way of greeting. 14. My brother keeps ______ (help) me with my work. 15. We should often practise _______ (speak) English with each other. Unit 3 语法一：一般现在时的被动语态语法二：一般过去时的被动语态 语法三：一般将来时的被动语态 【练一练】I．用被动语态改写下列句子。
七年级上册知识梳理 这本牛津版的书比以前用的广州版要容易些，在词汇量上，课文难易程度 上都有所不同，整本书分为四个module，每个module有两个单元，共有八个单元大概有220 个单词，短语，相对于小学五六年级每册130、140单词量，它增加了一些。第一模块讲的是 自己的生活，第二模块讲的是自然界，第三模块讲的是旅行，第四模块讲的是娱乐时间。 第一个模块讲的都是与自己日常生活息息相关的内容，学会向他人介绍自己，怎样给朋友写 电子邮件，学会描绘自己的学校生活或业余生活，养成写英语日记的好习惯。 Unit 1 Making friends 重点单词、短语：Germa n, blog, grammar, sound, complete, hobby, country, age, dream, every one, Germa ny, mountain, elder, frie ndly, engin eer, world, Japa n, flat, yourself, us, close to, go to school, (be)good at, make fiends with, all over, =would like ‘lik to. 要掌握的句型：1. What does ? mean? 2. Welcome to ? 3. I like ? because ? 4. My dream is to be ? 5. How old is/are ? ? 6. What does ? do? 重难点知识：1.特殊疑问句，掌握what, which, how 等疑问词引导的句子，注意 区分how many 和how much, which 和what.
怎样使员工培养成本降低 当前职场较为复杂，企业发展需求也较为广泛，而主要需求依旧是人才方面，企业对于人力资源开发的重视已经有了很不错的成就，很多企业开始关注成本降低问题，下面就做一下简单介绍： 前阵子在武汉，一位颇具营销才干的女老板说，她最大的愿望是团队建设，找一批像我这样的人。言下之意，是想寻找一批和她一样优秀的老板级员工。听后，我大觉诧异，马上泼了一瓢冷水：恐怕你三年也找不到。 原因有二，一是这样的人不属于你，既然他是一个做老板的料，一定会去当老板;二是像她这样优秀的，条件一定非常高，找到了也养不起。 如此说来，真的没有办法了吗? 那倒不是。真要找到像这位女老板一样优秀但用人成本却较低的人，办法还是有的。 比如，知识管理(KM)就可以。知识管理，就是运用集体的智慧提高应变和创新能力，是为企业实现显性知识和隐性知识共享提供的新途径。通过知识管理，把她的优秀技能和特质进行分解，并让其标准化、流程化和规范化，然后分别找到具有某类相同潜质的员工一一培养，一定可以组建一个像她那样优秀，且成本低的强有力的团队。 知识管理，是企业对其所拥有的知识资源进行管理的过程。以这位女老板为例，她就是一种知识资源，通过识别、获取、开发、分解、储存、传递知识，从而使每个员工在最大限度上贡献出其积累的知识的同时，还能享用他人的知识。而实现知识共享，则是知识管理的目标，对知识资源进行管理的过程为知识向效益的转化提供条件，并且要对知识管理中员工的贡献进行评价和实施激励，以保证知识管理能得到足够的支持并发挥其作用。 知识管理是要找到一种方法或模式，把综合的、抽象的和复杂的知识分解为小的知识点，把抽象内容具体化、形象化。这样，员工可以比较快地了解知识点的具体内容，更快地掌握低一级的知识，减少员工学习新知识的时间和困难。有一种工作分解结构法，值得效法。通过对女老板的知识进行分解和评价分析，找到一种能很好地帮助知识管理者进行知识分解和评价的方法。尽管组织吸收和集聚全面的、抽象的和复杂的知识有很大难度，但解决
八年级（下）复习之语法归纳与练习 【练一练】．单项选择。 ( ) 1. Our teacher gave us 10 minutes __________ about the question. A. thinks B. to think C. thinking D. thought ( ) 2. My father decided ________smoking. A. giving up B. to give up C. give up D. to giving up ( ) 3. You may take a horse to the river, but you can't make it________. A. to drink B. drank C. drink D. drinking ( ) 4. I didn't ask him ______to my party, but he came. A. to come B. come C. came D. coming ( ) 5. You can use a tool ________ a fire. A. make B. making C. to make D. to making 【练一练】I．单项选择。 ( ) 1. __________ the train means waiting for another hour. A. Miss B. Missed C. Missing D. To missing ( ) 2. After _______his homework he went on to write a letter to his parents. A. finishes B. finishing C. finished D. to finish ( ) 3. _________ may cause cancer. A. Smoking B. Smoked C. Smoke D. To smoking ( ) 4. As she is looking forward to __________ from me, please remember to send this letter to her as soon as possible. A. hear B. hearing C. heard D. be heard ( ) 5. Grandma said that she had a lot of trouble __________ your handwriting. A. to read B. read C. reading D. to reading ( ) 6. Writing stories and articles __________ what I enjoy most. A. is B. are C. was D. were II．用括号内所给动词的适当形式填空。 7. He came to the party without ________ (invite). 8. It took the workmen only two hours to finish ________ (repair) my car. 9. ________ (keep) your room clean is a way to stay away from disease. 10. He is very busy _______ (do) his homework. 11. Please stop _______ (talk), boys. I have something important to tell you. 12. Before ______ (buy) the house, you should get somebody to look it over. 13. ________ (sh ake) hands is a way of greeting. 14. My brother keeps ______ (help) me with my work. 15. We should often practise _______ (speak) English with each other. 【练一练】I．用被动语态改写下列句子。 1. The mother looked after the baby in the room. _____________________________________________________________ 2. My sister cleans the bedroom every day.
Unit1 单词： German 德国的 blog 博客 grammar 语法 sound 声音 complete 完成 hobby 爱好 country 国家 age 年龄 dream 梦想 everyone 人人；所有人 Germany 德国 mountain 山；山脉 elder 年长的 friendly 有好的 engineer 工程师 world世界 Japan 日本 flat 公寓 yourself 你自己 US 美国 短语： ask somebody about 就……询问某人live……with 与……一起生活 close to (在空间上、时间上)接近 go to school 去上学 (be) good at 擅长 make friends with 与……交朋友 all over 遍及 ’d like to=would like to 愿意 (be) far from 远离 best wishes 最美好的祝愿 on the Internet 在互联网上 in my free time 在我的业余时间hear from somebody 收到某人的来信
Unit2 单词： daily 日常的 article 文章 never 从不 table tennis乒乓球 ride 骑；驾驶 usually 通常的 so 因此；所以 seldom 不常；很少 Geography 地理 break 休息 bell 钟；铃 ring (使)发出钟声；响起铃声 end 结束；终止 band 乐队 practice 练习 together 在一起 market 集市；市场 guitar 吉他 grade 年级 短语： once or twice a week 一周一两次 brush one’s teeth 刷牙 junior high school 初级中学 love/enjoy doing…喜欢做…… on foot 步行 morning break 早间休息 take part in 参加 have a good time=enjoy oneself 过得愉快 in the evening 在晚上 later in the afternoon 下午晚些时候 play the guitar 弹吉他 do morning exercises 做早操 go to bed 去睡觉 have breakfast/lunch 吃早餐/午餐 get up 起床 wash one’s face 洗脸 a piece of bread 一块面包 have dinner 吃晚饭 arrive at 到达 help somebody with something 帮助某人做某事
如何降低人力成本 欧阳光明（2021.03.07） 一、理清人力成本观念 1.等级制“害人” 人与人之间是平等的，工作上的“总经理”、“总监”等称呼是由分工不同决定的，如果公司的等级制度很严重，人力成本就会很高，而且不利于鼓励员工积极性。例如，有些公司出差时，级别高的人员可以住五星级酒店，级别低的人员只能住招待所，这样做是不正确的。 2.不要得“帕金森病” 企业如果得了“帕金森病”，就会出现以下现象：人浮于事、机构臃肿；人际关系紧张，勾心斗角，尔虞我诈；员工盛行加班，但不是真的有工作，而是做给老板看；汇报工作的员工少，打小报告的员工多，员工工作效率低下。老板要认真观察企业是否存在这些现象，如果存在，则说明企业得了“帕金森病”，要认真对待。 3.鼓励专业的人做专业的事或爱好的事 企业应该鼓励专业的人做专业的事和爱好的事，专业的事和爱好的事重合是最好的现象，如果二者发生冲突，最好以爱好为导向。 4.鼓励“好马吃回头草” 有些员工离职一段时间后又回到了公司，公司应该鼓励这种现象。需要注意的是，“吃回头草”的一定要是“好马”，如果一个
员工是由于道德品质的原因离开，这样的员工就不是“好马”，企业不应该再次接收。 人力部门要对离职的员工进行科学管理，尤其是高管人员和中层以上的领导，要定期跟踪他们，一旦企业某个岗位有空缺，而曾经离职的管理者在其他企业又不如意，邀请他再次回到公司，也是一件很好的事情。从成本的角度来说，“好马吃回头草”是很划算的。 5.专业分工不要过细 企业分工不应过细，尤其是小企业，分工如果太细，一是不利于培养合格的员工，二是浪费成本。市场是无情的，自己企业成本高，竞争对手成本低，企业就走上了被淘汰的路。 6.节省人工成本不等于低工资 有些老板认为裁员和降薪是节省人力成本的主要方法，其实，这是节省人力成本最忌讳的两个方法。节省人工成本要实现双赢，就要注意以下几点： 缩短工作时间，提高工作效率 有些民营企业每星期工作六天，这样非常不利于降低成本。因为工作时间长不代表工作效率高，而且员工加班不代表敬业，企业反而要为员工的加班支付加班费。 计划管理 企业应该使所有事情都按计划进行，谨记“没有计划不做事，没有预算不花钱，没有目标不经营”。管理的第一职能就是计划，按照计划做事，才能实现双赢。 提高熟练程度，积累专业经验
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。
Unit 1 Helping those in need 一、要点概括 1.短语 in need, voluntary work, ask peimission, suffer from, raise one’s spirits, in order to, continue to do, pay for, work as 2.句型 (1)There are many children without parents. (2)They have difficulty walking or moving. (3)I am thingking about doing some voluntary work. (4)I am going to do some voluntary work. (5)Since then, this project has helped millions of girls return to school. (6)I wish to help other girls the way the Spring Bud Project helped me. 二、疑难宝典 1. courage 勇气，勇敢 amazing courage 惊人的胆量cool courage 镇定勇气 He hurt his leg in an accident, but he has lots of courage. They do not have the courage to apologise for their actions. 2. illness （某种）病 bear illness 忍受疼痛cure illness 治愈疾病combat illness 与疾病斗争 He died at the age of 83 after a long illness. 3. in order to 目的在于，为了 In order to raise money for children in need, we are going to sell old books. She worked all summer in order to save enough money for a holiday. 4. lonely adj. 孤独的，寂寞的 She is unhappy and very lonely. 【区别】lonely＆alone alone单独的（意为没有其他人陪伴）；lonely孤独的（因为没有他人的陪伴而难受） 5. offer 主动提出[ + to do sth. ]表示愿意（做......） Three teenagers offered to do some voluntary work during the school holidays. He offered to get me a cab. 6. peace 宁静，平静（n.）peaceful adj. 宁静的 I taught them to sing because music can bring them joy and peace. After a busy day, all I want is peace and quiet. 7. raise 筹募，增加，提高 We need to help children like Tim and raise their spirits. They are raising money for charity. Please raise standards. 【区别】raise＆rise raise意思是将某物抬举或举到较高的位置，或者增加数量、提高水平，后面必须跟宾语。 rise意思是增加或上升，后面不接宾语。 8. There be句型表示存在，意为“某地有某物”。Be动词应与紧跟其后的主语的单复数形式 保持一致。主语是不可数名词或单数可数名词时用is或was，主语是复数可数名词时用are 或were。 There is some bread on the plate. There are seven days in a week.
新版广州七年级(初一)英语上册单词表-２０1４年1月13日更新Modｕｌe 1My LifｅUnｉt1＆Ｕnit２ Unit１Making Frｉenｄs Ｇｅrman?德国的 Blog???博客 Grａｍmar??语法 Ｓound??听起来、声音 Cｏmｐｌete 完成 Hｏbby 爱好 Countrｙ国家、向下 Ａgｅ???年龄 Dream??梦想，做梦 Eｖeｒyｏnｅ每个人 Germａｎy 德国 Ｍountain 山脉 Ｅlder ?年龄较大的,年长的 Fｒieｎdly?友好的 Eｎgｉneer 工程师 Wｏrｌd?世界 Japaｎ?日本 Ｆlat??平房，平坦的 Yourself 你自己 US 美国 cｌose to??靠近 gｏｔo schoｏｌ??去上学 be gｏod aｔ擅长 makｅ friendｓ with?和。。。交朋友 ａｌl ｏvｅｒ??遍及 ’d like to =would likｅ to 想要 Unｉt2Dａily Lifｅ Daily??每天的，日常的 Artｉclｅ文章 Ｎever?从不 tａble teｎnｉs?乒乓球 Riｄｅ?骑 Usually?通常 So??所以 Seldｏｍ很少 Ｇｅographｙ地理 Ｂrｅaｋ??打破 Ｂeｌl??铃 Ring??铃响
Eｎd???结束 Band ?乐队 Praｃtｉce??练习 Togetｈｅr 一起 Maｒket?市场 Guitaｒ?吉它 Graｄｅ??年级 junior hiｇh school?初中 ｏn fooｔ??步行 takeｐart in??参加 haｖe a good time 玩得开心 go to bed??上床睡觉 get up???起床 Moduｌe 2 Ｔhe Natural WorｌｄUnit３& Unit4Ｕnit３Tｈe Eａｒｔh Eaｒｔｈ???地球 Quiz????测试 Ｐattｅｒn??模式 Proteｃt ?保护 Repｏrt??报告 Paｒt?部分 Land???陆地 Fieｌｄ?田野、田地 Ｌargｅ??大的 Ｐroviｄe 提供 Pｏllｕtｉoｎ污染 Bｕｒn???燃烧 Ｅnｅrgy ?能量 Ｐolｌｕｔe??污染 Ｉnto ??进入 Grｏｕnd ?地面 Ｋiｌl ?杀死 Muｓｔ?必须 Ｉmｐoｒtａnt ??重要的 Fact???事实 Ｋilｏmｅｔer??千米 Oｗn?自己的 Caｔcｈ???抓住 Ｆew????很少 Aｗay ?离开 Prｏblem 问题 ｐroviｄe wｉth ?提供。。。
关于公司节约成本的具 体方案 Pleasure Group Office【T985AB-B866SYT-B182C-BS682T-STT18】
关于公司节约成本的具体方案 作为一个自主经营，自负盈亏的企业来讲，不光要潜心研究怎么挣钱如何创造效益，更要考虑如何节约成本，降低损耗。俗话说：“不省不成家”，企业就是一个大家庭，只有这个“大家”发展了，们各自的“小家”才会殷实，也就是印证了“大河有水小河满，大河无水小河干”的这句话。 最初我理解的公司节约，只考虑到了节约水电等能源方面的节约，缺忽视了还有其他很多方面。针对集团公司目前的状况，从三个方面着手精简公司成本。 一.集团公司的能源节约。主要为节电 电的使用主要集中在照明设备电灯、电脑饮水机、和空调三个方面 水的成本主要在饮用水上面。公司的饮用水分为两种，分别是饮水机上大桶升的桶装水和农夫4升桶装水。其中大桶装水升，每桶10元，农夫桶装水每桶4升，每桶7元。 尽量做到以下几方面： 1.白天上班时间除非室内采光不足，否则不开启室内照明灯。 2.人走关灯，人来开灯，外出办公超过半小时离开时需关闭电灯，电脑。否则一经 发现罚款10元 3.空调恒定开在26度，关机后须断电。对于下班没关电脑（包括显示器）的员工， 罚款10元，以示批评。 水的成本主要在饮用水上面。公司的饮用水分为两种，分别是饮水机上大桶18升的桶装水和农夫4升桶装水。其中大桶装水升，每桶10元，农夫桶装水每桶4升，每桶7元。
目前情况下，每周平均使用7桶大桶装水和40桶农夫纯净水。如果提高大桶纯净水的使用量而降低农夫桶装水，则是一笔可观的费用。 二．集团公司的办公费节约。 由财务部财务总监计算出当月办公费使用的大体金额，主要包括纸张、墨盒、一次性口杯、易损耗的其他办公用品。立足当月，参照前几月，做出下月的办公费预算，月底检查完成情况，如果超支了，则要找出超支的重点，从源头上控制浪费。 纸张双面打印提倡了很多年，但我发现很少时候能做到。我觉得问题的关键不是大家不知道双面打印节省纸张，而在于很少人能在打印的时候把用过的纸放进打印机里。没有人做这个动作，那打出来的东西就只能是单面的、一次性的。解决这个问题，可以出台规定，除了公司重要文件不允许直接使用白纸打印。另外将打印过的纸张放到打印机放的显眼地方，方便看到使用。（这个动作我已经做了）即使双面打印的纸张在不是完全看不清的情况下仍旧可以留下来当草稿纸。 在采购的时候同时采购相应的内件产品，中性笔、圆珠笔的笔芯，活页本的内页。都可以增加办公用品的使用寿命。 对于每月的办公成本实际支出低于预算的这部分钱可以拿出来发给员工作为奖金，谁节约谁受益，以便更好的调动员工积极性参与公司降低成本的活动，又可以培养员工好的工作习惯。或是将这部分钱定向用于公司年会奖品的购置。 三．损耗管理--降低损耗，修旧利废。库存是成本，减少不必要的库存对于有破损的大件办公用品，如桌椅，电脑、空调，在无法修理或修理成本太高的情况下，建议一次性处理，直接卖掉。毕竟库存也是成本，减少不必要的库存，其实就是节省了仓库空间，减少库管的工作量。
2018 年广州版英语八年级下册 Unit 2 期末复习资料 Unit 2 Body language 跟踪练习 用所给单词的适当形式填空 1. Y ou had better practise (exercise) every day. 2. J im does his homework as (care) as his brother. He never makes mistakes. 3. W hat about 4. T hey answered the questions (have) a picnic? (different). 5. T hey learn English by (sing) English songs. 单项选择 1. You don’t give people a good , so people choose Debbie instead of you. A. impression B. instruction C. impressive D. instruct 2. Disney is famous for its cartoon characters Mickey Mouse, Donald Duck, Goofy and Snow White. A. for example B. such as C. as D. likes 3. The film me of my father. I miss him very much. A. promises B. reminds C. makes D. returns 4. Yesterday I an invitation from Tom but I didn’t it. A. received; receive B. accepted; accept C. accepted; receive D. received; accept 5. I’m with the homework, Mom. A. bore B. bored C. boring D. to bore 6. --- In this example, is not important. --- Yes. We shouldn’t judge a person his or her look. A. appearance; by B. appearance; for C. expresion; by D. expresion; for 7 W hat time will you arrive China? ---- I don’t know. Maybe five hours . A. at; later B. in; later C. at; late D. in; late 8 W hat’s the with you? --- I didn’t know the of this sentence. A. wrong; communication B. matter; communication C. wrong; meaning D. matter; meaning III ．Grammar （动名词的用法） 基本用法： 1.作主语 (谓语用三单) Swimming in the sea is her favourite sport. 2.作宾语（动词及介词的宾语） I practise speaking English every day. Debbie is good at communicating with people. 3.作表语（表示主语是什么，可主表互换） My biggest hobby is collecting stamps. 4.作定语（说明所修饰事物的用途） There is a swimming pool nearby.
腾飞教育 初一英语上讲义 第一讲Unit1 Making friends Name: Mark: 一、课文单词与短语 German adj. 德国的 blog n. 博客 grammar n. 语法 sound n. 声音 complete v. 完成 hobby n. 爱好 country n. 国家 age n. 年龄 dream n. 梦想 everyone pron. 人人，所有人 Germany adj. 德国 mountain n. 山；山脉 elder adj. 年长的 friendly adj. 友好的 engineer n. 工程师 world n. 世界 Japan n. 日本 flat n. 公寓 yourself pron. 你自己. US 美国 close to （在空间，时间上）接近 go to school 去上学 (be) good at 擅长 make friends with 与…….交朋友 all over 遍及‘d like to =would like to 愿意 二、课文内容精析 1. Welcome to my blog. welcome to sp. 欢迎来到某地 2. I’m from Germany. 我来自德国。be from= come from 来自 Germany 德国 German adj. 德国的 n.德语；德国人（two Germans） German cars are very good. She was born in Germany. The Germans speak English very well. 3. I’m 11 years old. 我十一岁。 问句：What is his age = How old is he 他多大了 1) at the age of= when sb. was … years old 在……岁的时候 He could swim at the age of six. = He could swim when he was six years old 2）the same age of = as old as 和……一样大 She is the same age of Kate. = She is as old as Kate. （注意：the same height as = as tall as 和……一样高； the same length as = as long as 和……
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
广州版初中英语八年级下册期末复习 Unit 1 Helping those in need I. Key words 1. 区分raise / rise 2. 区分offer/provide 3. 区分lonely/ alone II. Key phrases 1.give sb a hand = help sb 2.offer to do 主动提供做某事 3.suffer from sth. 受…之苦，受….折磨 4. a girl called Cindy = a girl named Cindy 5.help sb do sth/ help sb with sth 6.have difficulty in doing sth 7.raise one’s spirits 使振奋，使鼓起勇气= cheer sb up 8.something dangerous 危险的事 9.would like to do 10.because of/ because 跟踪练习： 用所给单词的适当形式填空 1. In order ________________(learn) Japanese, he went to Japan. 2. Daming has great difficulty ________________(speak) English. 3. Do you know the girl _______________(call) Alice? 4. Shenzhen has a population of over ten ________________( million ) 5. ______________(help) others makes me happy. 单项选择 1. May I have a rest ? I have already finished ________the report. A. write B. writing C. to write D. written 2. --I feel a bit hungry now. -- Why not ________for dinner with us? A. go B. did you go C. to go D. do you go 3. He asked her ________the bag because it was too expensive . A. not to buy B. to buy not C. not buying D. not buy 4. Although you may meet with some difficulties, you should never ________. A. turn up B. get up C. give up D. grow up 5.--- Would you like to go to the hospital to help the sick kids this Sunday? --- ________. I’ll be free then. A. Sorry, I can’t B. Not at all C. Thank you D. Sure, I’d love to 6. Is there _______ in today’s newspaper?