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This study purposed to experimentally investigate the seasonal operating performance of the packaged unit of a hollow membrane-based ventilation system. The packaged unit of the proposed ventilation system was fabricated, and the experiments was conducted based on the test standards for the energy recovery ventilator addressed from air-conditioning, heating and refrigeration institute (AHRI). In addition, for achieving the optimal heat and moisture recovery from the ventilation system under various operating conditions, the seasonal operation modes were suggested for the packaged unit of the proposed ventilation system. The measured data showed that the proposed ventilation unit can provide the ventilation air ait nearly neutral air temperature and humidity ratio in each operation mode. In addition, the average sensible effectiveness, the average latent effectiveness, and the average enthalpy effectiveness of the proposed ventilation system are 70.7%, 75.9%, and 75.6% in mode 1; 44.4%, 74.7%, 80.2% in mode 2; 77.6%, 70.4%, 85.6% in mode 3, which exhibited the higher heat and moisture recovery performance compared to the commercial energy recovery ventilator. In conclusions, the measured data demonstrates that the proposed ventilation system has a great application potential for building ventilation unit in terms of energy recovery performance., CLIMA 2022 conference, 2022: CLIMA 2022 The 14th REHVA HVAC World Congress

As passive building systems improve, sensible loads decrease and the air conditioning system takes on a greater role in dehumidification. Isothermal dehumidifier with membrane, which utilizes a vacuum pump to create a partial vapor gradient between membranes, has the potential to save significant energy by operating just for latent cooling as a thermally decoupled system. Although research has concentrated on analyzing the dehumidification and energy performance of isothermal dehumidifiers via simulation studies, their design and experimental analysis for dehumidification systems in HVAC systems remain rare. In this study, we constructed a prototype of an isothermal dehumidifier using hollow fiber membrane modules and vacuum pumps for an air conditioning system. Under different air conditions, the constructed prototype was evaluated for dehumidification characteristics (i.e., isothermal process, moisture removal rate, and dehumidification efficacy). Three factors were used to choose the air conditions for testing the dehumidification performance: air temperature, air humidity, and air velocity. The experiment results indicated that the isothermal dehumidifier dried the air without changing the temperature, and the overall dehumidification performance of the prototype system indicated that the humidity ratio difference was between 3.8 and 14 g/kg, the moisture removal rate was between 0.12 and 1.0 kg/h, and the dehumidification effectiveness was between 36% and 81%., CLIMA 2022 conference, 2022: CLIMA 2022 The 14th REHVA HVAC World Congress

In this study, a water-to-air type hollow-fiber membrane humidifier was built, and its humidification characteristics were experimentally investigated under various test conditions. A humidification module made of a porous hollow-fiber membrane in which hydrophilic and polymeric raw materials are mixed was used. Using the selected material, shell-and-tube structured hollow-fiber membrane module was fabricated and tested under various operating conditions. The experimental data showed that the proposed membrane modules exhibited 74.5%–91.7% humidification effectiveness and moisture transfer of 2.5–15.8 g/kg under various operating conditions; furthermore, the modules could provide humidifier performance with few temperature changes. The results of the parametric analysis indicated that the inlet water temperature was a critical factor affecting the humidification heating performance of the proposed system but did not show a clear effect of the water flow rate.

A simplified model of a polymer electrolyte membrane (PEM) fuel cell has been suggested for simulating packaged commercial fuel cell systems. PEM fuel cell systems are used in building cogeneration applications because of their high efficiency, low transmission loss and pollution, flexible scalability, and low noise. In conventional cogeneration applications, optimization techniques are utilized to size a system and determine proper operational strategies using simulations. To evaluate the performance of a building cogeneration system, a fuel cell model should be concise but accurate to allow its implementation in a whole-building simulation program. Some existing models are appropriate for building applications, but they have some limitations in modeling when a commercial packaged fuel cell system is used. To overcome these problems, a simplified fuel cell model is suggested for commercial packaged fuel cells by adding some new variables and validating through experimental and published data. This model is relatively simple compared to other models but can be easily utilized in some limited cases with performance predictions.