室內植栽牆對室內溫熱環境及空調節能效益之研究

Abstract

隨著都市的開發及人為的破壞，地球暖化及都市熱島越來越熱嚴重，人們停留在室內時間也隨之增加，在臺灣溫熱帶氣候要維持室內舒適環境必須仰賴空調設備，相對的也造成大量的能源消耗。如何透過節能的方式來達到有效舒適的室內環境，成為當前重要的議題。近年來植栽牆廣泛的被使用在室內空間上如機場及商場空間，許多文獻也指出植物有舒壓、降溫及淨化空氣溫等..提升室內環境品質等效益，由此可知植栽牆對於增加室內舒適度及空調節能上有很大的潛力。但回顧文獻大部分植栽牆的研究多著墨於植栽牆附掛於建築外牆後對室內溫熱環境的影響，鮮少研究直接探討室內植栽牆對室內舒適度的影響。因此本研究從室內舒適度的觀點著手，來探討植栽牆對室內溫熱境境的影響以及空調節能上的效益，提供設計者未來在使用室內植栽牆時參考依據。本研究採用全尺度實驗室以自動連續量測法進行室內環境因子的監測。在實驗規劃上為了增加研究結果的應用性，將實驗分成兩個階段，第一個階段將貨櫃屋模擬鐵皮屋室內空間，第二個是貨櫃屋增設隔熱層模擬一般居住空間，分別進行室內舒適環境觀測及空調實驗。在第二個階段中進行不同綠覆率實驗，提供植栽牆使用時合適綠覆率參考。在室內舒適度分析上採用ASHRAE之熱適應模型及ISO7730的PMV-PPD模式，雙重模式進行室內舒適度分析。 此外，為擴及評估夏季過熱與冬季過冷之長期熱不舒適以彌補實測期間之不足，本研究建立室內植栽牆模型，運用EnergyPlus來進行全年逐時模擬，解析植栽牆對室內全年長期熱舒適之影響。模擬結果採用ISO 7730所建議之長期熱不舒適評估法，區分熱不舒適與冷不舒適，評估鐵皮屋於室內植栽改善前後之過熱與過冷之發生頻率及其嚴重程度差異，藉以量化室內植栽牆對提升室內熱舒適度之效益。 經由實驗結果可得知，室內增加植栽牆之後在不同季節對室內環境有不同影響。在冬季冷氣團時期，植栽牆會造成室內冷不舒適更嚴重，所以不適用。在春季時期鐵皮屋的室內空間下，室內植栽牆可提供降低室內空氣溫度1.52度及平均輻射溫度2.6度的效益，並且淨化室內二氧化碳濃度55.7ppm的效益。在夏季時期貨櫃屋增設隔熱層的室內空間下，室內植栽牆可降低室內空氣溫度3.5度及平均輻射溫度3.7度效益，但是卻會提高室內二氧化濃度110.9ppm。在室內舒適度上，經由熱適應模式分析結果，室內增加植栽牆可以提升室內舒適度。但是在PMV-PPD模式分析結果，室內增加植栽牆反而增加室內不舒適，主要原因為室內植栽牆增加室內相對濕度的緣故所造成。所以建議室內使用植栽牆時需保持室內空氣流動，來改善植栽牆對室內造成空氣相對濕度增加的問題;在綠覆率實驗中，植栽牆綠覆率1/2對於達到室內舒適環境的效益最好，主要原因為夏季高溫會造成植栽牆的土壤對室內環境的影響大於植物本身對室內環境的改善效益;在空調實驗中，室內增加植栽牆能有效降低用電量，一個月可節省8.64度電，夏季用電期間可節省116.9元。在EnergyPlus模擬全長期不舒適度嚴重度及發生頻率上，可得知植栽牆適用於辦公類型空間中，能有效降低室內熱不舒適嚴重度及過熱現象的發生頻率。 綜合以上結果，室內空間使用植栽牆可提升室內舒適度並且降低用電量，但是必須保持室內空氣流動改善室內濕度增加的問題。

Along with the urban development and the man-made destruction, global warming and urban heat island have become a growing phenomenon, which increase the time people staying indoors. In subtropical Taiwan, it relies on air conditioner to maintain a comfortable indoor environment; however, it causes significant energy consumption. Therefore how to achieve a comfortable and energy- effective indoor environment becomes an important issue nowadays. In recent years, the vegetated wall is widely used for the interior spaces, such as airports and commercial areas. Many researches already pointed out that vegetation help release human’s pressure, cool down the air temperature, and purify the air…etc. Based on these many benefits, it’s supposed that vegetated wall have great potential to improve the quality of indoor environment and save up more energy. Most of the research done on the theme of vegetated wall shed light on the influence brought to the indoor thermal comfort after the vegetated wall were attached to the exterior surface of a building. Therefore my research will approach from the perspective of the vegetated wall set inside the building, and how it can improve the indoor comfort.The research quantified the indoor thermal effect of the vegetated wall by experiment in two full –scaled laboratories. The experiment was divided into two stages. In the first stage the experiment measured the indoor environment condition of the metal sheet house. In the next stage, the house was added an insulation layer to simulate common residential houses. On the indoor comfort analysis using the adaptive model of ASHRAE and the PMV- PPD model of ISO7730, that dual model analysis of indoor comfort was divided into two stages for better research results. The research simulated the annual long-term vegetated effect on hourly indoor thermal condition by Energyplus.in order to assess the degree of over cool and over heat alleviated by vegetated wall during cold period and hot period. Simulation results using long-term thermal discomfort analysis suggested by ISO 7730 show the difference between thermal discomfort and cold discomfort, and to evaluate the before and the after when the vegetation is added to the metal sheet house. By calculating the frequency and severity of thermal discomfort and cold discomfort, the results can be quantified for assessing the efficiency of the vegetated wall to promote the indoor thermal comfort. Through the experimental results, increasing the indoor plant wall in different seasons has different influences on the indoor environment. During the cold winter, this wall can cause coolness so it does not apply. In the spring period, the vegetated wall could provide a reduction of 1.52 degrees indoor air temperature and 2.6 degrees Mean Radiant Temperature, and purified indoor CO2 concentration for 55.7 PPM. In the summer period with added insulation layer in the indoor space, the vegetated wall could reduce 3.5 degrees indoor air temperature and 3.7 degrees Mean Radiant Temperature, but increase 110.9 PPM the indoor CO2 concentration. As for the indoor thermal comfort analysis, increasing the vegetated wall can improve the indoor comfort. But PMV-PPD model shows that the house with vegetated wall is more discomfort than the house without vegetated wall. This is the main reason the vegetated wall increases humidity. So suggesting vegetated wall which maintain indoor air flow improves the problem of the increase in humidity. In the green cover experiment, the green wall layer rate is 1/2 to achieve the best comfortable indoor environment. The main reason for this is the summer heat can cause the garden soil of the wall's influence on the indoor environment to be greater than the plant itself on the indoor environment. In the air conditioning experiments, the indoor added green wall can effectively reduce power consumption, saving 8.64 KWH per month during the summer season could save 116.9 TWD. In the EnergyPlus simulation on the severity and frequency of discomfort over a long period of time, we can learn that the vegetated wall is suitable for the appropriate type of office space, thus the wall can effectively reduce the severity and frequency of the indoor overheating phenomenon. To conclude the above results, the interior space using the vegetated wall can improve indoor comfort and lower power consumption, under the circumstance of maintaining indoor air flow which helps prevent the increase of humidity indoor.