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.

scholarly journals Numerical Analysis and Preliminary Experiment of a Solar Assisted Heat Pump Drying System for Chinese Wolfberry

Energies ◽  
2020 ◽  
Vol 13 (17) ◽  
pp. 4306 ◽  
Author(s):  
Zhongting Hu ◽  
Sheng Zhang ◽  
Wenfeng Chu ◽  
Wei He ◽  
Cairui Yu ◽  
...  
Keyword(s):  
Energy Consumption ◽  
Heat Pump ◽  
Electric Energy ◽  
Energy Performance ◽  
Operating Conditions ◽  
Pump System ◽  
Heat Pump System ◽  
Electric Energy Consumption ◽  
Drying System ◽  
Heat Pump Drying

The present work investigated a solar assisted heat pump system for drying Chinese wolfberry. The kinetic characteristic was firstly analyzed through a series of lab experiments. It was concluded that the Page model was the most suitable for predicting the heat and mass transfer of the wolfberry. Based on the wolfberry kinetic model, solar collector model and chamber air model, the coupled drying system model was developed. The accuracy of the mathematic model was determined through comparing with the preliminary experimental results. The influence of operating conditions on the thermal and energy performance of the dryer for the different operating mode was discussed. The drying weight of no more than 75 kg may be preferable in the stand-alone solar drying mode, and less than 15 h was needed to be dried. The electric energy consumption in the solar assisted the heat pump drying mode was lower than that in the stand-alone heat pump mode, and it was recommended that about 50 kg of wolfberry to be dried in the solar assisted heat pump system. Compared to the autumn drying, the reduction in the electric energy consumption was around 9.1 kWh during the 11 h summer drying process. The obtained results demonstrated the feasibility of the combined system for drying wolfberry, and also can provide the basic theoretical and experimental data support for the following research.

DETERMINING THE PROFITABILITY OF GREENHOUSE ELECTROTECHNOLOGIES: A MODELING APPROACH

HortScience ◽  
1994 ◽  
Vol 29 (4) ◽  
pp. 249a-249
Author(s):  
Eric A. Lavoie ◽  
Damien de Halleux ◽  
André Gosselin ◽  
Jean-Claude Dufour
Keyword(s):  
Energy Consumption ◽  
Heat Pump ◽  
Water System ◽  
Heat Pumps ◽  
Hot Water ◽  
Pump System ◽  
Heat Pump System ◽  
Artificial Lighting ◽  
Hot Air ◽  
Marketable Fruit

The main objective of this research was to produce a simulated model that permitted the evaluation of operating costs of commercial greenhouse tomato growers with respect to heating methods (hot air, hot water, radiant and heat pumps) and the use of artificial lighting for 1991 and 1992. This research showed that the main factors that negatively influence profitability were energy consumption during cold periods and the price of tomatoes during the summer season. The conventional hot water system consumed less energy than the heat pump system and produced marketable fruit yields similar to those from the heat pump system. The hot water system was generally more profitable in regards to energy consumption and productivity. Moreover, investment costs were less; therefore, this system gives best overall financial savings. As for radiant and hot air systems, their overall financial status falls between that of the hot water system and the heat pump. The radiant system proved to be more energy efficient that the hot air system, but the latter produced a higher marketable fruit yield over the 2-year study.

Energy Consumption Modeling of a Heat Pump System for Combined Space Conditioning and Residential Water Heating in a Typical Household in Quito, Ecuador

2016 ◽  
Author(s):  
Gabriel Agila ◽  
Guillermo Soriano
Keyword(s):  
Energy Consumption ◽  
Heat Pump ◽  
Thermal Storage ◽  
Hot Water ◽  
Water Heating ◽  
Water Heater ◽  
Pump System ◽  
Detailed Model ◽  
Heat Pump Water Heater ◽  
Residential Water

This research develops a detailed model for a Water to Water Heat Pump Water Heater (HPWH), operating for heating and cooling simultaneously, using two water storage tanks as thermal deposits. The primary function of the system is to produce useful heat for domestic hot water services according to the thermal requirements for an average household (two adults and one child) in the city of Quito, Ecuador. The purpose of the project is to analyze the technical and economic feasibility of implementing thermal storage and heat pump technology to provide efficient thermal services and reduce energy consumption; as well as environmental impacts associated with conventional systems for residential water heating. An energy simulation using TRNSYS 17 is carried to evaluate model operation for one year. The purpose of the simulation is to assess and quantifies the performance, energy consumption and potential savings of integrating heat pump systems with thermal energy storage technology, as well as determines the main parameter affecting the efficiency of the system. Finally, a comparative analysis based on annual energy consumption for different ways to produce hot water is conducted. Five alternatives were examined: (1) electric storage water heater; (2) gas fired water heater; (3) solar water heater; (4) air source heat pump water heater; and (5) a heat pump water heater integrated with thermal storage.

scholarly journals THE HEAT PUMP SYSTEM FOR VENTILATION AND AIR CONDITIONING INSIDE THE PRODUCTION AREA WITH AN EXCESSIVE INTERNAL MOISTURE GENERATION

2020 ◽  
Vol 17 (2) ◽  
pp. 78-86
Author(s):  
M.K. Bezrodny ◽  
Keyword(s):  
Energy Efficiency ◽  
Relative Humidity ◽  
Heat Pump ◽  
Air Conditioning ◽  
Warm Season ◽  
Pump System ◽  
Heat Pump System ◽  
Environment Temperature ◽  
Production Area ◽  
Continental Climate

The paper studies application feasibility and energy efficiency of the ventilation and air conditioning heat pump system for maintaining comfort conditions inside the production area with an excessive internal moisture generation during the warm season. In this regard, a thermodynamic analysis of a heat pump system with a partial exhaust air recirculation and a variable ratio of fresh outside air was carried out. Numerical analysis was then done to estimate the influence of changes in the environment temperature and relative humidity and the characteristics of the ventilation and air conditioning object on the system parameters. This allowed to determine potential capabilities of this system to maintain comfortable conditions in the production area. It was also shown that the required additional cooling of the supply air at the entrance to the premise for air conditioning demands can be determined by a simple coefficient and its calculation method is provided in the article. The heat pump system of temperature and humidity maintenance has the highest energy efficiency in the zone of relatively low environment temperatures and largely depends on the relative humidity of the outside air. This suggests that the studied system is suitable for application in countries with temperate continental climate.

Comparisons of Thermodynamic Performance of Three Types of Air-Conditioning Systems Under Ideal Processing Procedure

2020 ◽  
Vol 13 (2) ◽  
Author(s):  
Donggen Peng ◽  
Danting Luo ◽  
Yuting Fu
Keyword(s):  
Control System ◽  
Relative Humidity ◽  
Heat Pump ◽  
Hybrid System ◽  
Low Grade ◽  
Independent Control ◽  
Pump System ◽  
Heat Pump System ◽  
Study Results ◽  
The Ideal

Abstract As the substitution of the traditional heat pump system, the heat pump driven liquid dehumidification hybrid system and the temperature-humidity independent control system have great application potentials. In this paper, the ideal reversible processes of the three types of systems are built theoretically with their mathematical models, in order to compare their maximum coefficients of performance COPs. The results show that the COP1 of the ideal heat pump driven liquid dehumidification hybrid system is the maximum and the COP2 of the temperature-humidity independent control system is the minimum with the COP3 of the heat pump system falling between both. The COP1 increases by 100% with an increase in the indoor design temperature and relative humidity while the COP1 decreases with the increase in the ambient temperature and relative humidity. The COP2 of the temperature-humidity independent control system can be affected more significantly by supply air temperature difference and angle scale. In an ideal heat pump system, low-grade heat source utilized to reheat the processed air is a superior choice. The study results in this paper have guiding significance for the selection of three types of systems in practical applications.

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.

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