地源熱泵應用於建築之供暖和製冷性能分析及改善

Abstract

本研究利用宜蘭地下水資源作為淺層溫能來源，透過抽取地下水和熱泵進行直接熱交換，形成地源熱泵系統應用於建築中的供暖和製冷需求。淺層溫能具有溫度穩定的特性，作為熱泵中蒸氣壓縮冷凍循環中的冷源或熱源都能有效降低壓縮機之負荷，就能減少耗電量，達到節能的效果。 實驗對本地源熱泵系統的三種模式進行分析，三種模式藉由冷媒不同循環所做區分，分別為沒有利用淺層溫能同時製熱水和冰水的雙效模式、製熱模式、製冷模式。結果顯示雙效模式的製熱COP可達3.3；製冷COP為2.1，製熱模式因有淺層溫能減少高壓端的負荷，製熱COP可達到4.2。除了製熱水外，藉由改變水路管線使熱水能經過風機模擬暖氣，數據顯示可使出風口溫差達到40°C，具備市面暖氣機性能，室內和室外的溫差可達8°C，符合中央空調系統之標準。製冷模式COP可達6.3，冰水經過風機能使出風口溫度達15°C，符合夏季冷氣水系統出風口溫度，冷房能力可達20.8kW，相當於7噸冷氣效能。 本熱泵系統的冷媒管線在製冷模式上有兩片熱交換器串聯之情形，透過水側進水順序不同可達到回收冷媒在熱水端熱交換器所散失的部分顯熱，使製熱COP可達5.47，相比原本製熱模式的COP上升30%。利用此管路配置進行雙效模式測試，也能分別提升製熱COP達3.6約上升8%；製冷COP達2.5約上升16%。

This research explores the use of groundwater resources in Yilan as a shallow geothermal energy source. The approach involves extracting groundwater and utilizing heat pumps for direct heat exchange, creating a ground source heat pump system for heating and cooling in buildings. Shallow geothermal energy exhibits temperature stability, effectively reducing the compressor load in the vapor compression refrigeration cycle of heat pumps when used as a cold or heat source. This reduction leads to lower power consumption, achieving energy efficiency. The experiment analyzes three modes of the local ground source heat pump system, distinguished by different refrigerant cycles: the dual-effect mode that simultaneously produces hot water and ice water without utilizing shallow geothermal energy, the heating mode, and the cooling mode. Results indicate that the dual-effect mode achieves a heating COP of 3.3 and a cooling COP of 2.1. The heating mode, benefiting from shallow geothermal energy, reduces the high-pressure side load, resulting in a heating COP of 4.2. Additionally, by modifying the water pipeline, hot water can be simulated through a fan to achieve an outlet temperature difference of 40°C, meeting central heating system standards with an indoor-outdoor temperature difference of 8°C. In the cooling mode, the COP reaches 6.3, and the use of ice water through a fan achieves an outlet temperature of 15°C, meeting the requirements for summer air conditioning system outlet temperature. The cooling capacity can reach 20.8 kW, equivalent to the performance of a 7-ton air conditioner. The refrigerant pipeline in this heat pump system features two heat exchangers in series during the cooling mode. Varying the water inlet sequence allows the recovery of sensible heat lost in the heat exchanger at the hot water end, resulting in a heating COP of 5.47 and 30% increase compared to the original heating mode COP. Testing the dual-effect mode with this pipeline configuration also leads to an increase of approximately 8% in the heating COP (reaching 3.6) and 16% increase in the cooling COP (reaching 2.5).