熱濕氣候下之室內冷水牆效益評估研究

新形態輻射冷卻系統之冷水牆已被開發，然而過去皆於溫帶氣候下進行相關的研究與探討，其尚未被應用於熱濕氣候下。本研究針對該系統之特性與文獻，延伸探討熱泵系統應用於熱濕氣候下的冷房、除濕、節能、水資源利用，甚至於淨化空氣的可能性。藉由冷水牆原型實驗，驗證冷水牆的冷房與除濕效果，並將實驗結果進行熱舒適探討，確認冷水牆被應用於熱濕氣候下，人員進行靜態活動時的室內熱舒適感受。於空氣淨化實驗，採用游離粉塵(PM2.5)作為影響因子，探討冷水牆對於室內空氣品質(IAQ)的改善潛力。冷水牆由一座面積2 m2的不鏽鋼材內嵌清玻璃構成、平均供水溫約16.8 °C於室溫31 °C、相對濕度61.7 %的2.1 m3隔熱艙體中，使用水流量300 l/hr、500 l/hr、700 l/hr進行實驗，其冷房能力分別為1,033.4 Kcal/hr、1,917.1 Kcal/hr以及2,627.7 Kcal/hr；而實驗後所對應的熱舒適評估(PMV)分別為-0.41、-1.18與-0.87，熱感受介於中性(neutral)至稍微冷(slightly cool)，其呼應熱帶使用者的自適應熱感受偏好；啟動冷水牆的空氣淨化效益提前約28分鐘使室內PM2.5沉降至環境初始值，而三種流量的空氣淨化效益相差不大。
經由實驗數據結果建立計算流體力學(CFD)模型並予以驗證後，模擬各水流量的冷房與除濕效益，同時了解空間中的氣流分布，並提出相關的設定參數與邊界條件，供未來研究者進行冷水牆再現性實驗或進一步的模擬運算與研究探討，亦可作為室內設計師進行設計規劃，將冷水牆與空間進行整合設計(如：引入植栽綠牆或水幕造景等)之參考。

A chilled water wall as a new type of radiant cooling system has been developed. Previous studies have explored the use of the system in a temperate climate. Its application in a hot and humid climate has not been explored. The present study used the characteristics and relevant studies of the system to explore the possibility of using a heat pump system for room cooling, dehumidification, energy saving, water resources utilization, and air purification under hot and humid climates. The chilled water wall prototype experiment was conducted to verify the room cooling and dehumidification effectiveness of the chilled water wall. The experimental results were adopted to identify the thermal comfort of people in sedentary activity in an indoor environment that applied the chilled water wall under a hot and humid climate. In an air purification experiment, fugitive particulate matters (PM2.5) were determined as an influential factor in exploring the potential of the chilled water wall in improving Indoor Air Quality. The chilled water wall was composed of a 2-m2 stainless steel wall embedded with colorless glass. The average temperature of the supplied water was approximately 16.8°C at a room temperature of 31°C, and the relative humidity was 61.7% in the 2.1-m3 thermal insulation chamber. The water flow rates at 300, 500, and 700 l/h were used for experiments and the resulting room cooling capacities were 1,033.4, 1,917.1, and 2,627.7 Kcal/h, respectively. The thermal comfort evaluation (predicted mean vote) values for the three flow rates were −0.41, −1.18, and −0.87, respectively. The thermal perception was between neutral and slightly cool, corresponding to the adaptive thermal perception preferences of tropical users. The air purification effectiveness after activation of the chilled water wall enabled the indoor PM2.5 to precipitate to the initial environmental value approximately 28 min earlier. However, the three flow rates did not yield much difference in the effectiveness of air purification.
Experimental data results were used to establish and verify computational fluids dynamics models. The models were used to simulate room cooling and dehumidification effectiveness of different flow rates and understand the air flow distribution in the space. Relevant design parameters and boundary conditions were proposed to help future researchers reproduce the chilled water wall experiment or conduct further simulated computation and exploration for interior designers during design planning. The integration design of the chilled water wall and the space (e.g., introducing green walls or water curtain landscape) can serve as a reference.