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In this work, an analytical model is presented to show the air leakage effect on the heat transfer within a permeable 120 mm thick, fiber glass wall. Both steady-state and steady periodic conditions are considered for the inner and the outer surfaces of the wall. Computer calculations are made to determine the temperature profiles and heat flux variations within the wall taking into consideration the infiltration and exfiltration of air. The effect of air flows on the heat transmission through the wall is studied and the thermal advantages of the circulating air through the building walls are analyzed. The study is concentrating on the thermal performance of dynamic walls integrated in a whole building, as a function of the infiltration and exfiltration rates and the building thermal load. The results indicate that the dynamic walls can save energy of up to 20 percent of the total building thermal load

In this work, the enthalpy potential theory is used in conjunction with a formula derived by Uchida and a set of data available on the cooling tower of Baghdad international airport to predict the thermal performance of a mechanical draft counter flow cooling tower of closed type.Computer calculations are made to determine the number of transfer units, water-cooling range and tower capacity. The computer results are presented in graphical form as performance curves showing the predictable thermal performance of the tower under different conditions of air inlet wet bulb temperature and water-to-air flow ratio, when the load on the tower, denoted by the water inlet temperature, remains unchanged. The results indicated that the performance of the tower and hence its capacity are affected by the air inlet wet bulb temperature and the water-to-air flow ratio. They face a considerable decline with increase of air inlet wet bulb temperature and with increase of water-to-air flow ratio too. Then, the decline with increase of air inlet wet bulb temperature reduces with increase of water-to-air flow ratio. The agreement of the present results with results of the others and with measurement would give a sufficient support to the analysis adopted in this work.