本論文では，地下水流動存在下の地中熱交換器周囲温度を計算する手法を，深度毎に分割することで複層地盤に対応させた，地中熱交換器内部熱媒温度の計算モデルについて示した．また，計算モデルを応用して，熱応答試験時に得られる見かけ上の有効熱伝導率から，地下水流動の存在する層の全層に占める割合や地下水流速を推測する方法について検討した．結果より加熱時間50 h の熱応答試験で得られる見かけ上有効熱伝導率が4.5 W･m-1･K-1 を超えると，全層に対して25％以上の地層で300 m･ y-1 以上の地下水流動があることが示唆された．また，地下水流速が300 m･y-1 以上の地層が存在する地点での熱応答試験では，経過時間50 h から150 h における見かけ上有効熱伝導率の上昇率に対する，地下水流動の存在する層の全層に占める割合は，ほぼ一致することが確認できた．
Horizontal ground heat exchanger in ground source heat pump systems is susceptible to ground surface variations thus affecting its thermal performance. However, this configuration is desirable due to low installation costs as it mainly involved burying pipes in shallow trenches. The optimization of horizontal ground heat exchanger was investigated by simulating a cross section of the ground containing a single unit of slinky-loops. The analysis shows that although trench depth increased by one third in vertical orientation, there was no significant improvement on thermal performance compared to horizontal orientation. Unless land area is limited then it is suggested that loops are installed in vertical orientation. When the material used as ground heat exchanger was copper pipe, heat exchange rate improved by 20% compared to conventional HDPE pipe. As expected, ground thermal resistance has a limiting effect on thermal performance although the pipe was changed to a material with thermal conductivity of over 800 times higher. The effect of distributing the flow into a group of loops in parallel was also examined. Thermal performance increases as more heat transfer area was provided in parallel loops. The spacing between adjacent loops was studied to elucidate heat interference in parallel loops operation.
This paper presents theoretical and experimental investigation of an adsorption cooling system to predict the cycle performance of one bed adsorber based on the equilibrium condition. For this particular study, activated carbon-ethanol pair was chosen as the adsorbent-refrigerant pair because of a high adsorption capacity of activated carbons against ethanol. The experiment was conducted on five different pre-cooling and pre-heating settings. The experiments carried out were divided to two sections. First, the preliminary experiments were carried out on two extreme conditions. For the first extreme condition, the adsorption and desorption process were carried out without pre-cooling and pre-heating. Whilst for the second extreme condition, the adsorbent was pre-cooled and pre-heated until the adsorbent reach adsorption and desorption temperature. Then the experiments were carried out with three different time of pre-cooling/pre-heating time which was selected based on the preliminary experiments. The heat balance were analyzed critically and the optimum cycle time, namely the pre-cooling and pre-heating time for each adsorption and desorption process is discussed by identifying the suitable adsorbent pressure and temperature of the system.