scholarly journals Effect of Evaporator Position on Heat Pump Assisted Solid Desiccant Cooling Systems

Energies ◽  
2020 ◽  
Vol 13 (22) ◽  
pp. 5918
Author(s):  
Shuo Liu ◽  
Chang-Ho Jeong ◽  
Myoung-Souk Yeo
Keyword(s):  
Energy Consumption ◽  
Heat Pump ◽  
System Performance ◽  
Indoor Environment ◽  
High Humidity ◽  
Comfort Zone ◽  
Upward Trend ◽  
Cooling Systems ◽  
Desiccant Wheel ◽  
Extra Energy

The packaged terminal air conditioning with reheat (PTACR) system, as a commonly used dehumidification system, faces the problem of extra energy consumption in the deep-cooling and reheating processes. Therefore, different heat pump assisted hybrid solid desiccant cooling (HPDC) systems were proposed and their characteristics were investigated via EnergyPlus simulations. The system energy efficiency presents an upward trend with the increase in outdoor temperature and humidity. A high-humidity climate leads to the improvement of system performance. The dehumidification performance of the desiccant wheel in the HPDC system declines when outdoor humidity increases. Compared with the PTACR system, the energy consumption of the HPDC system in which the evaporator was placed upstream of the desiccant wheel is reduced by 36%, 66%, and 64%, respectively, under different high-humidity climates. The system maintained the indoor environment within the comfort zone, and eliminated the need for a heat source for desiccant regeneration. In conclusion, the HPDC system is an available alternative that considers both energy consumption and system performance. Placing the evaporator upstream of the desiccant wheel is more advantageous in high-temperature and high-humidity climates.

Performances of Heat Pump Driven Two-Stage Desiccant Plates Dehumidifier for Residential Application in Humid Climate

2017 ◽  
Author(s):  
Rang Tu ◽  
Yunho Hwang
Keyword(s):  
Energy Consumption ◽  
Heat Pump ◽  
System Performance ◽  
Switching Time ◽  
Southern China ◽  
Plate Thickness ◽  
Humidity Ratio ◽  
Humid Climate ◽  
Two Stage ◽  
Rain Season

Buildings in southern China have high dehumidification demands in summer, especially during plum rain season. To investigate the dehumidifier properly working under high humid and high temperature climate, this paper introduced a residential solid desiccant dehumidifier, which has three features, namely desiccant plate dehumidification, heat pump driven and two-stage configuration. This dehumidifier is designed to process the indoor air to the required humidity ratio to meet the humid dissipation demand and the outdoor air is used to regenerate the dehumidifier. The residential application of this dehumidifier in humid climate was discussed in this paper through simulation. First, a heat pump driven two-stage desiccant plate dehumidifier was designed and modeling methods were introduced. Second, parametric studies were carried out, and the influences of plate thickness, switching time, air flow rate and supply air humidity ratio on performances, such as energy consumption and system performance coefficient of this dehumidifier, were discussed. Lastly, the energy consumption and the system performance coefficient of this dehumidifier were compared with those of traditional mechanical dehumidifier using vapor compression cycle. The results show that the switching time is recommended as 3 to 5 minutes. The discussed dehumidifier can meet the residential dehumidification demand in humid climate, and the performances are greatly enhanced as compared with the traditional condensing dehumidifier due to high evaporating temperature and no need of reheat.

scholarly journals Research on Energy-Saving Experimental of Critical Dehumidification of Combined Drying by Dehumidification Wheel and Heat Pump

2021 ◽  
Vol 2021 ◽  
pp. 1-11
Author(s):  
Jiaoling Wang ◽  
Weidong Song ◽  
Chengqian Jin ◽  
Tianhang Ding ◽  
Mingyou Wang ◽  
...  
Keyword(s):  
Energy Consumption ◽  
Relative Humidity ◽  
Heat Pump ◽  
Color Difference ◽  
Pump System ◽  
Drying Temperature ◽  
Desiccant Wheel ◽  
Conversion Point ◽  
Heat Pump Drying ◽  
Drying Quality

In order to further decrease the energy consumption of desiccant wheel dehumidification, the drying medium circulation characteristics of a system combining heat pump drying with desiccant wheel dehumidification were investigated. Moreover, the critical dehumidification conversion mechanism was studied. The analysis of the heat pump hot air circulation system demonstrated that the heat pump system has the best dehumidification efficiency. Through the analysis of the system combining heat pump drying with desiccant wheel dehumidification, the critical conversion point was determined. The critical dehumidification mechanism was further verified using an online temperature and humidity measurement system. To investigate the effect of the critical point on energy consumption and drying quality and develop a drying model, response surface experiments were performed based on the effects of regeneration temperature, drying temperature, and conversion point relative humidity on rehydration, color difference, and specific moisture extraction rate (SMER). The optimal conversion point humidity was determined to be about 46% RH, which was slightly different from the test optimization value of 45.6% RH. In addition, comprehensive optimization and experimental verification of the influencing factors were conducted. The results demonstrated that the R2 values of the three models were greater than 0.98, and the experimental factors had a significant effect on drying quality and energy consumption. When the regeneration temperature was 96°C, the drying temperature was 53°C, the relative humidity of the conversion point was 46%, the color difference was 46.3, the rehydration ratio was 5.75, and the SMER was 1.62 kg/kW·h.

Saving Primary Energy Consumption Through Exergy Analysis of Combine Distillation and Power Plant

2012 ◽  
Vol 9 (2) ◽  
pp. 65
Author(s):  
Alhassan Salami Tijani ◽  
Nazri Mohammed ◽  
Werner Witt
Keyword(s):  
Energy Consumption ◽  
Power Plant ◽  
Heat Pump ◽  
Heat Recovery ◽  
Energy Savings ◽  
Primary Energy ◽  
Heat Pumps ◽  
Saturated Steam ◽  
Distillation Unit ◽  
Primary Energy Consumption

Industrial heat pumps are heat-recovery systems that allow the temperature ofwaste-heat stream to be increased to a higher, more efficient temperature. Consequently, heat pumps can improve energy efficiency in industrial processes as well as energy savings when conventional passive-heat recovery is not possible. In this paper, possible ways of saving energy in the chemical industry are considered, the objective is to reduce the primary energy (such as coal) consumption of power plant. Particularly the thermodynamic analyses ofintegrating backpressure turbine ofa power plant with distillation units have been considered. Some practical examples such as conventional distillation unit and heat pump are used as a means of reducing primary energy consumption with tangible indications of energy savings. The heat pump distillation is operated via electrical power from the power plant. The exergy efficiency ofthe primary fuel is calculated for different operating range ofthe heat pump distillation. This is then compared with a conventional distillation unit that depends on saturated steam from a power plant as the source of energy. The results obtained show that heat pump distillation is an economic way to save energy if the temperaturedifference between the overhead and the bottom is small. Based on the result, the energy saved by the application of a heat pump distillation is improved compared to conventional distillation unit.

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