建筑环境与能源应用工程专业英语9.ppt

1,Lesson Three Heat Pumps,2,Topics,What is heat pump? (the definition and working theory),Classification of heat pump systems,Typical heat pump systems flow sheet and their characters,Work site pictures,Text and key words learning,3,heat pump reversing valve heating cycle cooling cycle indoor coil outdoor coil frost defrost energy efficiency ratio (EER) coefficient of performance (COP) heating seasonal performance factor (HSPF) seasonal energy efficiency ratio (SEER) ambient temperatures air-source heat pump water-source heat pump ground-water heat pump geothermal closed-loop heat pump,heat pump 热泵 reversing valve 四通换向阀 heating cycle 制热循环 cooling cycle 制冷循环 indoor coil 室内盘管 outdoor coil 室外盘管 frost 霜 结霜 defrost 除霜 energy efficiency ratio (EER) 能效比 coefficient of performance (COP) 性能系数 heating seasonal performance factor (HSPF) 制热季节性能系数 seasonal energy efficiency ratio (SEER) (制冷)季节能效比 ambient temperatures 室外气温 air-source heat pump 空气源热泵 water-source heat pump 水源热泵 ground-water heat pump 地下水源热泵 geothermal closed-loop heat pump 闭环地源(或土壤源)热泵,Frequently used words and phrases,4,What is heat pump? A heat pump extracts heat from a source and transfers it to a sink at a higher temperature. According to this definition, all pieces of refrigeration equipment, including air conditioners and chillers with refrigeration cycles, are heat pumps. In engineering, however, the term heat pump is generally reserved for equipment that heats for beneficial purposes, rather than that which removes heat for cooling only.,Topic one: Heat pump-Definition,5,Topic one: Heat pump-working theory,6,Heating season,T1,T2,T3,T4,Topic one: Heat pump-working theory,7,Cooling season,Topic one: Heat pump-working theory,T3,T4,T1,T2,8,Air source heat pump Water loop heat pump Ground source heat pump,Topic Two: Classification of Heat pump systems,Therefore: Open you mind,comprehend by analogy,9,Air source heat pump,Topic Three: Typical heat pump systems -Air source heat pump,Cool water,Air,10,Benefits recovers heat from some zones and delivered to others provides a simple method of zone control provides a high level of reliability for both heating and cooling modes reduces piping costs transfers actual maintenance and repair costs to building tenants,Water loop heat pump,Topic Three: Typical heat pump systems -Water loop heat pump,T4,11,Terminology The term ground-source heat pump (GSHP) is applied to a variety of systems that use the ground, groundwater, or surface water as a heat source and sink. Included under the general term are ground-coupled (GCHP), groundwater (GWHP), and surface water (SWHP) heat pumps. Many parallel terms exist (e.g., geothermal heat pumps (GHP), earth energy systems and ground-source (GS) systems) and are used to meet a variety of marketing or institutional needs.,Topic Three: Typical heat pump systems -Ground-source heat pump-Terminology,12,Ambient air,Earth,Grounder water,Topic Three: Typical heat pump systems -Ground-source heat pump-Advantages,13,Ground source heat pump,Ground-Coupled Heat Pump,Direct expansion GCHP,Groundwater Heat Pump,Surface Water Heat Pump,Open-loop SWHP,Closed-loop SWHP,GCHPs with secondary solution loops,Horizontal,Vertical,Topic Three: Typical heat pump systems -Ground-source heat pump-Classification,14,Vertical GCHP,The advantages of the vertical GCHP is it (1) requires relatively small plots of ground, (2) is in contact with soil that varies very little in temperature and thermal properties, (3) requires the smallest amount of pipe and pumping energy, and (4) can yield the most efficient GCHP system performance.,The disadvantage is it is typically higher in cost because of expensive equipment needed to drill the borehole and the limited availability of contractors to perform such work.,Topic Three: Typical heat pump systems -Ground-source heat pump-Ground coupled (vertical),15,Disadvantages include, in addition to larger ground area requirement, greater adverse variations in performance because (1) ground temperatures and thermal properties fluctuate with season, rainfall, and burial depth, (2) slightly higher pumping energy requirements, and (3) lower system efficiencies.,Horizontal GCHP,The advantages of horizontal GCHPs are that (1) they are typically less expensive than vertical GCHPs because relatively low cost installation equipment is widely available, (2) many residential applications have adequate ground area, and (3) trained equipment operators are more widely available.,Topic Three: Typical heat pump systems -Ground-source heat pump-Ground coupled (Horizontal),16,Advantages: 减少中间换热环节，提高效率 管材耗量可以减少 地下施工量相对减少，不需要防 冻剂 Disadvantages： 地下换热器成本较高，但同时减 少了二次换热管路 制冷剂易泄漏,Direct expansion GCHP,Topic Three: Typical heat pump systems -Ground-source HP-Ground coupled (Direct expansion),17,Groundwater Heat Pumps,Disadvantages are that (1) local environmental regulations may be restrictive, (2) water availability may be limited, (3) fouling precautions may be necessary if the wells are not properly developed or water quality is poor, and (4) pumping energy may be high if the system is poorly designed or draws from a deep aquifer.,Topic Three: Typical heat pump systems -Ground-source heat pump-Groundwater heat pump,The advantages of GWHPs under suitable conditions are (1) they cost less than GCHP equipment, (2) the space required for the water well is very compact, (3) water well contractors are widely available, and (4) the technology has been used for decades in some largest commercial systems.,18,Surface Water Heat Pump,The advantages of SWHPs are (1) relatively low cost (compared to GCHPs) due to reduced excavation costs, (2) low pumping energy requirements, (3) low maintenance requirements, and (4) low operating cost.,Disadvantages are (1) the possibility of coil damage in public lakes and (2) wide variation in water temperature with outdoor conditions if lakes are small and/or shallow. Such variation in water temperature would cause undesirable variations in efficiency and capacity, though not as severe as with air source heat pumps.,Topic Three: Typical heat pump systems -Surface-water heat pump,19,Topic Three: Typical heat pump systems -Surface water heat pump (open loop),Topic Three: Typical heat pump systems -Surface water heat pump (closed loop),20,Heat balance,Key problem Heat balance,21,1. A Brief History history of heat pump 2. The Efficiency of a Heat Pump EER COP 3. Types of Heat Pumps Air-source Heat Pumps Water-source Heat Pumps Ground-water Heat pumps Closed-loop Heat Pumps,Topic Five: Text learning and keywords,22,The basic principle of heat pump operation was first proposed by Nicholas Carnot in 1824 and then furthered by Lord Kelvin in 1852. 2. Rather than utilizing water as the heat source, most manufactures put their energies into air-source heat pumps, because many designers were under the mistaken impression that ground water resources were limited.,propose: 提出 提议 further: 促进（发展） 拓展,put their energies into: 把精力投入到中去 be under the mistaken impression: 误解,Topic Five: Text learning and keywords,23,3. One air-source heat pump manufactured during this period reversed air flow over the coils rather than reversing the flow of the refrigerant.,reverse: 颠倒(流向) reversing valve: 换向阀,Topic Five: Text learning and keywords,4. In other words, when called upon for cooling, the indoor air was directed over the indoor coil; when called upon for heating, the indoor air was directed over the outdoor coil.,call upon(on): 要求 号召 direct: 引导 指导 direct a letter to a place Can you direct me to the railway station? indoor coil: 室内盘管 outdoor coil: 室外盘管,24,5. At the same time, air conditioning equipment was gaining in popularity and efficiency; 6. In an effort to equalize power loads, power companies began an active promotional campaign in support of heat pumps, in spite of the fact that the equipment was still not perfected.,equalize: 补偿、平衡 power loads: 电力负荷 active: 积极的 promotional campaign:推广活动 促销活动,gain: 增加 获利,Topic Five: Text learning and keywords,25,7. The Arab oil embargo of the early 1970s finally brought home the message to the American people that alternative energy sources warranted serious consideration. 8. Although research continues today in an effort to further improve efficiency, the general consensus is that the heat pumps being manufactured for todays market are a significant achievement.,Arab oil embargo: 阿拉伯石油禁运 weapon embargo towards China alternative energy sources: 替代能源 warrant: 保证 确保,further: 进一步地 consensus: 多数人的意见 舆论,Topic Five: Text learning and keywords,26,9. The equipment is cost effective, reliable, and a viable alternative to conventional heating and cooling methods