[工學(xué)]建筑環(huán)境學(xué)chapter41-2thermalcomfortable(1)(參考版)
2025-03-25 02:33本頁面
【正文】 解：設(shè)熱泵按逆卡諾循環(huán)運(yùn)行，根據(jù)題意， t1= 95 ℃ ， t2= 13℃ n pu te n e r g y P u m p ou t pu t e n e r g y H ea t C O P211H ???? TTT pump energy input :10kW heat energy output: 熱泵從環(huán)境中取得的熱量 供熱量中 注冊設(shè)備師考試題 ? 冬季 利用熱泵為房屋供暖，使室內(nèi)溫度保持在 20℃ ，需要向室內(nèi)供熱 3000W，室外環(huán)境溫度為 5℃ ，試求該熱泵的熱泵性能系數(shù)（供熱系數(shù)）？ ? 帶動該熱泵工作所需要的最小功耗是多少？ ? ? Heat sources for heat pumps ? Air ? Earth ? Water ? Exhaust heat A geothermal heat pump system. Summary of chapter 2 Nature of heat, its measurement and its effect 熱的性質(zhì)、量度和作用 Heat transfer 熱傳遞 Gases and vapours, and their effects 氣體和蒸氣，及其作用 Refrigerators and heat pumps 制冷機(jī)及熱泵 useful sentence patterns： XX is the standard SI unit of YY ?焦耳是國際單位制中能量的單位 ?開爾文是國際單位制中溫度的單位 Table XX gives YY values for a variety of materials ?表（ ）給出了不同材料的（ 比容 ） 值 xx will be discussed in later chapter. ? 這些問題在以后的章節(jié)中會講到。 Heat Pump 制冷機(jī)和熱泵 ? Refrigeration: 制冷 The transfer of heat from lower temperature regions to higher temperature is called refrigeration. ? Refrigerator: 制冷機(jī) Devices that produces refrigeration are called refrigerators. ? Refrigerant:制冷劑 The working fluid used in refrigerators are called refrigerant. ? Heat Pump:熱泵 Refrigerator used for the purpose of heating a space by transferring heat from a cooler medium are called heat pump. Can be divided into: 1） pression refrigerator and heat pump cycle 壓縮式制冷機(jī)和熱泵循環(huán) 2） absorption refrigeration cycle 吸收式制冷循環(huán) The refrigeration cycle 制冷循環(huán) 1） pression refrigerator and heat pump cycle 壓縮式制冷機(jī)和熱泵循環(huán) Four main ponents： Compressor 壓縮機(jī) Condenser 冷凝器 Expansion valve 膨脹閥 Evaporator 蒸發(fā)器 Four main ponents of a kitchen refrigerator. 2） absorption refrigeration cycle 吸收式制冷循環(huán) Not every gas behaves in a way that is suitable for the cycle of vapourliquidvapour changes used in refrigeration. A refrigerant must be below its critical temperature, or it will not liquefy, and it must be above its melting point, or else it will solidify. in general a useful refrigerant should possess the following properties: ? Low boiling point 低沸點 ? High latent heat of vaporisation 高的氣化潛熱 ? Easy liquefaction by pression 壓縮后容易液化 ? Stable, nontoxic and noncorrosive 穩(wěn)定、無毒無腐蝕 ? Environmental safety 對環(huán)境無害 Refrigerants :制冷劑 ? Chlorofluorocarbon (CFC) is a mixture of anic pounds contain carbon碳 , chlorine氯 , and fluorine 氟 ? freon 氟利昂 . ? It is now accepted that CFCs help cause a reduction of the ozone layer臭氧層 in the upper atmosphere of the earth and contribute to global warming of the World’s weather systems. CFCs ) 氟氯碳化物類 CFC replacements 氟利昂替代物 ? Ammonia 氨 is an efficient refrigerant but its toxicity and flammability requires special safety measures. ? Carbon dioxide 二氧化碳 is used in some large refrigeration plants and requires high operating pressures. ? Compression refrigeration cycle 壓縮式制冷循環(huán) ? Absorption refrigeration cycle 吸收式制冷循環(huán) refrigerators 制冷機(jī) A heat pump is a device which extracts heat from a low temperature source and upgrades it to a higher temperature. For a heat pump, The condenser coils are used to heat air or other medium Heat pumps 熱泵 ? The coefficient of performance (COPH) of a heat pump 熱泵的性能系數(shù) is the ratio of heat output to the energy needed to operate the pump 211H i n pu te n e r g y P u m pou t pu t e n e r g y H e a t C O PTTT???Heat pump efficiency ? 一熱泵功率為 10kW，從溫度為 13℃ 的周圍環(huán)境向用戶供熱，用戶要求供熱溫度為 95 ℃ 。 BTU Power P= H / t P Watt temperature T Degree Kelvin(K) thermometers Types: Temperature scales Celsius θ thermodynamic T Heat capacity c Density ρ = m/v ρ Kg/m3 Change of state Solid liquid gas interchangeable Sensible heat Latent heat expansion Now let’s move on to the second topic Heat transfer 傳熱 ? Heat energy always tends to transfer from high temperature to low temperature regions. ? three different modes of heat transfer. 1 Conduction 導(dǎo)熱 2 Convection 對流 3 Radiation 輻射 Conduction 導(dǎo)熱 is the transfer of heat energy through a material without the molecules of the material changing their basic positions. 物體各部分無相對位移或不同物體直接接觸時依靠分子、原子及自由電子等微觀粒子熱運(yùn)動而進(jìn)行
范文總結(jié)相關(guān)推薦
鄂ICP備17016276號-1