自製泛用型多功能熱泵於不同操作條件下 性能係數之探討

Abstract

本研究旨在建構兼具提供冷水、冷氣、熱水與暖氣的多功能熱泵系統，並探討各部熱交換元件在啟動或不啟動狀況、穩態或暫態運作條件下對系統及主機製熱與製冷性能之影響。系統組成包括壓縮機、蓄壓器、水對冷媒的板式熱交換器 (第一段熱排及冷排)、冷媒對空氣的熱交換器 (第二段熱排及冷排) 、二重管熱交換器、毛細管、感溫膨脹閥及液氣分離器。 系統組成選用壓縮機容量為1.5 USRT，第二段冷排與熱排使用的風扇均為60 W，熱水桶與冰水桶水量分別40 L為150 L，板式熱交換器中循環水的流量率為1160 L/hr，以上為固定條件。系統組成中擬探討的變動條件包括：蓄壓器容積比較、第一段冷熱排選用、毛細管長度評估與冷媒量評估。最後選定容積為0.77 L的蓄壓器，熱側第一段熱排選用熱傳面積為0.421 m2的板式熱交換器，冷側第一段冷排則選用熱傳面積為0.432 m2的板式熱交換器，選用長度為45 cm毛細管，冷媒量則選擇1.5 kg為填充量。在水溫自20 ℃加熱至50 ℃的過程中，以上組合的系統及主機的製熱性能係數可達2.87及3.38，系統及主機的製冷性能係數可達2.86及3.29，整體的系統及主機性能係數可達5.21及6.53。

The focuses of this study were to develop a generic multi-purpose heat pump capable of providing cold water, cold air, hot water and warm air at the same time, as well as to investigate on the impacts to the coefficient of performance of the system and the compressor due to various operating conditions in either high pressure and/or low pressure side of the refrigeration cycle, including on/off of the second stage heat exchangers and steady or transient state of water flow through water-air heat exchangers. This generic system consists of compressor, pressure accumulator, plate-type heat exchangers, air-water heat exchangers, dual pipe heat exchanger, capillary tube, thermal-controlled expansion valve and gas-liquid separator. The components selected for this generic design are as follows: capacity of the compressor is 1.5 USRT, power of fans of the air-water heat exchangers are 60 W, amount of water in the hot and cold water tanks are 40 L and 150 L, respectively, and the flow rate of the water re-circulating in both plate-type heat exchangers is 1160 L/hr. Subject to the components previously selected, other corresponding components were under investigation in order to reach highest COP, the selected components are: pressure accumulator at the capacity of 0.77 L, plate-type heat exchanger with the heat exchange area of 0.432 m2 at the cold (low pressure) side, and 0.421 m2 at the hot (high pressure) side, capillary tube at the length of 45 cm and amount of refrigerant R22 charged in to the cycle at the weight of 1.5 kg. With such combinations, the high pressure side of the COP of the system and compressor is 2.87 and 3.38, respectively, the low pressure side of the COP of the system and compressor is 2.86 and 3.29, respectively and the total COP of the system and compressor is 5.21and 6.53, respectively when the water temperature is to be raised from 20 C to 50 degree C.