A Case Study of a Pilot System with Gas-engine Heat Pumps and a Desiccant Air Handling System using Higher Chilled Water Temperature in Japan
A Case Study of a Pilot System with Gas-engine Heat Pumps and a Desiccant Air Handling System using Higher Chilled Water Temperature in Japan
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DOI：
10.1016/j.applthermaleng.2021.117817
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发表时间：
2021-11
影响因子：
6.4
通讯作者：
M. Ukai;Hideki Tanaka
中科院分区：
文献类型：
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作者：
M. Ukai;Hideki Tanaka
干燥剂空气处理机组（DAHU）是一种主要的除湿系统，其中吸附剂吸附湿空气。该系统需要热水来再生这些吸附剂。在这项研究中，安装了一个燃气发动机热泵（GHP），同时从发动机中提供冷冻和回收的热水作为DAHU的热源。由于大型除湿机不需要低温冷冻水进行冷凝除湿，因此研究了高温冷冻水对大型除湿机和整个系统的影响。在测量之前，研究了预冷盘管和后冷盘管后冷冻水温度的升高对空气状态的影响。根据初步审查，冷冻水温度的升高对空气状态没有影响，也就是说，干燥剂轮处的除湿量没有影响。冷冻水温度上限为13℃。在2019年夏季进行了两种冷冻水温度（7°C和12°C）的现场测量。两种工况的分析结果表明：提高GHP的冷冻水温度，使GHP的性能系数（COP）由0.8提高到1.0，而对大湖内的空气状态和室内热环境（温度和相对湿度）没有影响。总体而言，与整个系统相比，GHP的冷水和热水分配比例非常小，系统COP几乎相同，两者之间的COP约为0.73。然而，通过将冷冻水温度设定点从8°C提高到12°C，有可能使系统的能源性能提高4%。
A desiccant air handling unit (DAHU) is a major dehumidification system in which adsorbents adsorb moist air. The system requires hot water to regenerate these adsorbents. In this study, a gas-engine heat pump (GHP) with a simultaneous supply of chilled and recovered hot water from the engine was installed as a heat source for a DAHU. Because a DAHU does not require low-temperature chilled water for condensation dehumidification, the impacts of higher-temperature chilled water on a DAHU and the whole system were investigated. Preliminary to the measurement, the influence of the rise of the chilled water temperature on air state after pre-cooling coil and after-cooling coil was investigated. According to this preliminary reviews, the raise of the chilled water temperature does not affect on the air state, which means there is no influence of the dehumidification amount at desiccant wheel. Furthermore, the upper limit of the chilled water temperature is at 13˚C. Field measurements with two chilled water temperatures (7 °C and 12 °C) were conducted in summer 2019. The results from these two cases showed that the rise in the chilled water temperature of the GHP improves the coefficient of performance (COP) of the GHP from 0.8 to 1.0, without any influence on the air state in the DAHU or the indoor thermal environment (temperature and relative humidity). Overall, the distribution ratio of chilled and hot water from the GHP was very small compared to that of the whole system, where the system COP was almost the same, at approximately 0.73 between the two cases. However, there is a possibility to achieve 4% of better energy performance of the system by the increase of the chilled water temperature set point from 8 °C to 12 °C.