10.翻译：1.Vapor compression refrigeration system is composed by compressor，condenser，expansion valve andevaporator，connected with pipe line to form an enclosed system. Refrigerant changes heat with substance to be cooled in evaporator. Refrigerator absorbs heat from substance to be cooled and evaporated. The compressor draws the low pressure vapor in its suction side and then compressed it to high pressure before discharge.2.During the cycle, compressor, which is heart of the system, plays a part in compressing and transportingrefrigerant vapor and causing low pressure in evaporator and high pressure in condenser. Flow control valve throttles refrigerant flow to reduce its pressure and regulates refrigerant flow rate of entering evaporator.Evaporator, which is an equipment of refrigerating effect output, refrigerant absorbs heat form substance to be cooled to realize refrigerating. Condenser, which is an equipment of heat output, coolant in it takes away heat from refrigerant and heat from the work consumed by compressor.3.In liquid evaporating refrigerating systems, refrigerant is required to evaporate at low temperature. It absorbsheat from objects to be cooled. Then condenses at higher temperature and discharges heat to environment meanwhile. Therefore, only those evaporate and condense within range of working temperature can be used as refrigerants. Most refrigerants are in gaseous state at normal temperature and pressure.4.Mixed refrigerant is composed by two kinds or more pure refrigerants. Due to limitation to type andperformance of pure refrigerants, mixture of refrigerant offers more freedom to modulate performance and amplify choice of refrigerant.9翻译1. Boiler is a kind of heat exchange device which turns chemical energy and excess heat from industrial production process or other heat source into steam or hot water with certain temperature and pressure.2. According to heat transfer features of boiler, industrial boiler heat surface can be divided into radiant heat surface and convection heat surface. Radiant heat surface is that portion of surface of being located in combustion chamber and receive radiant heat. Manly means water cooled wall. Convection heat surface, located in boiler flue, is that portion of surface swashed directly by high temperature flue gas to transfer heat by convection.3. Boiler heat efficiency is an important technique index of boiler. Boiler heat efficiency means when boiler operating with rating load, how many percent of the heat from fully burning of fuel sent into boiler per hour to produce steam or hot water.4. Boiler has broad applications and various types. Some common criteria used in classifying them are: structure of boiler, application of boiler, fuel or energy used by boiler, type of combusting, ventilation mode, circulation mode and arrangement of boiler drum8 翻译1. HV AC means to realize regulating and controlling of temperature, humidity, cleanliness and air velocity for certain room or space, providing adequate fresh air meantime. HV AC is called Air conditioning for short. Air conditioning can realize overall controlling to heat and humidity environment and air quality in buildings, or to say it contains partial function of heating and ventilation.2. All -air system is a system that cooling or heating load in room is undertaken completely by air. An all-air system supplies sensible heat cooling capacity and latent heat cooling capacity by delivering cold air into room. Processes of cooling down and dehumidification of air are accomplished by air handling unit which locates completely in air conditioning machine room. Supplemental cooling in room is no more required, yet heat of supply air can be achieved either in air conditioning machine room or in individual room. Air treatment for all-air system is mainly centralized in air conditioning machine room, so it is commonly called central air conditioning system.3. Air -water system is a system that cooling or heating load in room is undertaken by both air and water. Besides supplying treated fresh air to room, terminal unit with circulation media of water installed in room heats and cools indoor air.7 翻译1. Ventilation is main approach to ensure indoor air quality. That is, displacing indoor air of higher contaminant concentration with outdoor air of much lower contaminant concentration. Ventilation rate needed should be determined by principle of diluting indoor contaminant to reach concentration specified by standard. Main contaminant source is people in people occupied buildings. So the requisite ventilation rate –fresh air rate is ascertained by people. That is, fresh air rate is ascertained by diluting carbon dioxide released by people. In order to take into account diluting other contaminant and odor aroused by people’s activity at the same time, many countries control carbon dioxide at 0.1%, while suggestion value of WHO is 0.25%.2. Air condition buildings are commonly well airtight. If no reasonable exists, indoor air quality in it is not better than common building with well ventilating. Ventilation issues are accomplished by air conditioning system except special treatment for hazardous gases released by technique process in air conditioning buildings. Special fresh air system is installed in air-water system to supply fresh air to individual room to fulfill task of ventilation and improve air quality. Outdoor fresh air should be introduced into all-air system and mixed with return air, and then the mixture is delivered to room to dilute indoor contaminant after been treated.3. Local air exhaust is a kind of local ventilation which removes contaminant directly from contaminant source. When contaminant occurs centrally in somewhere, local air exhaust is the most effective way to treat harm of contaminant to environment. If overall ventilation is adopted in such situation, contaminant may spread in rooms. When contaminant occurs in large amount, ventilation volume needed to dilute it can be too much to realize in practice. Local air exhaust system consists of exhaust hood、fan、air cleaner、air ducts、exhaust outlet.4. Nature ventilation caused by heat pressure or wind pressure is widely used ventilation. Common residential building, office building, industrial workshop depend on nature ventilation to ensure indoor air quality. Otherwise,natural ventilation is a kind of ventilation which is difficult to be controlled effectively. Only by understanding its basic principle and taking certain measure can we get nature ventilation going on according to out preset mode.5. Ventilation rate is always self-balanced practically when a room is ventilated. Air balance we referred to here means designing balance in the light of willing of designer or occupier. If balance designed has not performed, ventilation requirements may not be satisfied when system practically operates in balanced state. For example, a set of local exhaust system is installed to eliminate contaminant emitted by contaminant source in room. But the system doesn’t work well when operating and ventilation rate does n’t reach the need. The problem lies in that the room is in basement and has good air permeability performance. Meanwhile, absence of air intake system and passage gives rise to higher negative pressure and reduces ventilation rate of air exhaust system.6 翻译1. nature gas is generally divided into four kinds: gas exploited from gas well of gas field is called pure natural gas or gas of gas well; gas exploited accompanying with petroleum is called petroleum gas or petroleum accompanied gas; gas which has light fraction of petroleum is called condensate gas of gas field; gas drawn from coal bed of coal well is called coal mine well gas.2. Density variation should be taken into account when computing gas flow in pipes. Density of gas reduces with declining of pressure along the pipe line. Only in low pressure pipes the change in density of gas can be omitted.3. For the sake of making distribution system with very high economical index, optimal gas pipeline route is selected and number of gas pressure regulating room and distribution center is determined besides correct choice of pipe diameter. There are generally many kinds of design schemes to be encountered during the process of designing, therefore an optimal scheme should be picked out from them.5 翻译1. Heating by convection which is major type of heat transfer is called convection heating. Heat emitting equipment in the system is radiator, so this kind of system is also called radiator heating system. It supplies heat to room by heat convection. Radiant heating is a kind of heating type mainly by radiant heat transfer. Main heat emitting equipment of radiant heating system is metal radiant panel or part of ceiling、floor、wall of building as radiant surface.2. C irculating system can be divided into gravity circulating system and forced circulating system according to circulating power. System circulating by water density difference is called gravity circulating system. System circulating by mechanical force is called gravity circulating system. The force of gravity heating system depends on change of water temperature of the loop3. There are many factors influence heat transfer coefficient of radiator: manufacture condition of radiator (material, geometric dimension, structure form, spray coating of surface etc.) and application condition of radiator (media, temperature, flow rate, indoor air temperature and velocity, fitting type and combined piece etc.). They all synthetically influence heat emitting performance of radiator.4翻译1．Main issue of fluid dynamics is space distribution of velocity and pressure, velocity is more important between the two, inertia force and viscous force have close relationship with velocity. In the two forces, inertia force occurs with velocity variation of mass point itself while viscous force is caused by velocity difference between flow layers and mass points.2. Law of variation of viscosity coefficient with temperature is different between water and air. Viscosity of water reduces with increasing of temperature while increases for air. This is because viscosity is result of attractive force between articles and irregular thermal motion to arouse momentum exchange of articles. When temperature rises, attractive force between articles decreases and momentum increases. Conversely, when temperature decreases, attractive force between articles increases and momentum decreases.3. Heat transfer caused by density difference and gravity is called natural convection. Heat transfer coefficient of natural convection is generally lower than that of forced convection, therefore, when computing total heat gain or heat loss, the main point is radiant heat should not be ignored. Radiant heat transfer and natural convection may have the same order of magnitude even under indoor temperature conditions, because indoor wall temperature affects comfortable sensation of human body.3翻译1. Heat conduction is thought as heat transfers from high temperature zone to low temperature zone in object by gradually energy exchange with particles of substance. During the conduction, there is no specific displacement of articles. But for mental, motion of free electrons is greatly helpful to heat conduction.2. Fluid directly connected with the surface is heated and becomes less-dense by heat conduction and moves upwards due to density difference with adjacent fluid. This motion is hindered by viscosity of fluid. The heat transmission is affected by the following factors：（1）gravity caused by heat expansion；（2）viscosity （3）heat diffusionThis heat transmission is regard as depending on acceleration of gravity、coefficient of thermal expansion、coefficient of motion viscosity and coefficient of thermal conductivity.3. As for surface with different geometric shape, radiant characteristic and direction, when heat transfer rate is evaluated, assumptions are: (1) all surfaces are gray or black; (2) radiation or reflective diffuse reflection; (3) the whole surface parameters are homogeneous. (4) emissivity is equal to absorptivity and has no relationship with temperature of project source. (5) objects between two radiant surfaces neither emit nor absorb radiation. These assumptions are used due to providing simplification to large content, although the results are only thought as approximate.2 翻译1. Energy transfers between system and environment under temperature difference is called heat. Heat transfer of system and environment stops when system and environment are in thermal equilibrium. Once heat enters system through boundary, it turns into a part of system storage energy, that is, internal energy. It is obvious that heat is process factor relevant to process, while internal energy is state factor depending on thermodynamic state.2. T he Carnot cycle and Carnot theorem have important theoretical and impractical meaning in the research of thermodynamics. It provides upper limits on efficiency of heat engine and theoretically proposes the approach to increase efficiency. The efficiency of other impractical cycle is always less than the efficiency of the Carnot cycle operating between the same two reservoirs.3. The meaning of the increase of entropy principle：(1) estimate the direction of a process by the increase of entropy principle of an isolated system；（2）the increase of entropy principle can serve as judgment of system equilibrium-when entropy of an isolated system reaches maximum value，system is under equilibrium state. （3）the increase of entropy principle has close relationship with the irreversibility of a process. The more irreversible，the more increase of entropy. So it is used to evaluate perfect of thermodynamical performance of a process。
