The evacuated tube solar collector assisted heat pump for heating greenhouses

Hassanien, Reda Hassanien Emam; Li, Ming; Tang, Yilian

doi:10.1016/j.enbuild.2018.03.072

Cited by 84 publications

(29 citation statements)

References 32 publications

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“…The position of the heating source can be observed in Figure 1D. Hassanien et al [38] used an evacuated tube solar collector-assisted heat pump to heat greenhouses and concluded in his study that to provide the optimal heating requirements to crops, extra heating methods should be applied in December, January, and February. The maximum heating requirement was found in January and February.…”

Section: Discussionmentioning

confidence: 99%

Performance Evaluation of Root Zone Heating System Developed with Sustainable Materials for Application in Low Temperatures

et al. 2018

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The proposed system was developed to help the farmers of the Yangtze River Delta to grow greenhouse plants over winter, as the region has very low winter temperatures. For this reason, the experiment was undertaken during winter in extremely low temperatures to obtain optimal results. Keeping in mind the importance of sustainable practices, the authors developed the system using sustainable materials. The system was heated for 6 hours and then the hourly heat transfer rates were measured for 12 hours. The power consumption data of the heating system during different ambient temperatures were collected. Additionally, a simulation model of the heating system was developed using the COMSOL Multiphysics 5.3a package. The heat transfer in a porous media model was used in this study. Finally, the simulation results obtained from the COMSOL Multiphysics 5.3a package were analyzed and compared to the experimental results; these results were found to be in good agreement, thus authenticating the simulation model. After analyzing the data obtained from both methods, the power consumption of the heating system during different ambient temperature conditions were also calculated, which ranged from 15.73 W to 70.02 W in the simulated method and 28.2 W to 91.2 W in the experimental method. It was found that the root zone temperature remained in the range of 0-35 • C. This range of root zone temperature is suitable for many greenhouse horticultural crops such as tomato, cucumber, pepper, strawberry, lettuce, etc. The optimal root zone temperatures of many greenhouse horticultural plants are verified by many researchers.

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Section: Discussionmentioning

confidence: 99%

Performance Evaluation of Root Zone Heating System Developed with Sustainable Materials for Application in Low Temperatures

et al. 2018

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“…Type of System COP Year [28] Water source heat pump 4.9 2019 [29] Ethylene glycol water mix source heat pump 5 2020 [30] Water source heat pump 5.9 2020 [31] Water source heat pump 4.24 2018 [32] Ethylene glycol water mix source heat pump Winter 7.4 / Summer 6.5 2017 [33] Water source heat pump 5 2020 [34] Water source heat pump 4.9 2019 Table 4 shows that the average COP values of water source and ethylene glycol water mix source heat pump systems are between 4.24 and 7.4. This means that these heat pump systems can produce at least 4.24 times more heat than the electricity they consume.…”

Section: Referencesmentioning

confidence: 99%

Design of an innovative PV/T and heat pump system for greenhouse heating

Koşan

Akkoç

Dişli³

et al. 2020

Journal of Energy Systems

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The very high annual heat demand of greenhouses is the most critical factor that increases production costs. Conventional methods are generally used to obtain the optimum temperature required for greenhouses. In these systems, greenhouse air is heated by a boiler and pipe networks are connected to it, and in this way, most of the heat energy is transferred from the greenhouse ceiling to the atmosphere. In addition, in the greenhouse, not only the air but also the soil should be heated in order not to spoil the roots of the plants. The objective of this research is to provide sustainable heating for greenhouse applications. For this purpose, an innovative heating system has been designed for greenhouse heating by using of solar energy and heat pump technologies. In this study, a new approach was presented by designing a novelty heat pump flow for the heat required in the greenhouse. With this design, not only greenhouse air but also the soil will be heated and the best conditions for the development of plants will be provided. In the system, an ethylene glycol water mixture was used to prevent damage caused by freezing. In addition, it is designed to provide sustainability with an auxiliary heater when solar radiation is insufficient. It is highly recommended to apply this presented system for all greenhouse types.

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“…Additionally, they exhibit the ability to increase significantly the temperature of the working medium (up to 300 • C). Consequently, they are used in special industrial applications and generally, in every application that high temperatures are required [16,17].…”

Section: Solar Radiation For Thermal Energy Productionmentioning

confidence: 99%

Optimized Dimensioning and Operation Automation for a Solar-Combi System for Indoor Space Heating. A Case Study for a School Building in Crete

Katsaprakakis

Zidianakis

2019

Energies

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This article investigates the introduction of hybrid power plants for thermal energy production for the indoor space heating loads coverage. The plant consists of flat plate solar collectors with selective coating, water tanks as thermal energy storage and a biomass heater. A new operation algorithm is applied, maximizing the exploitation of the available thermal energy storage capacity and, eventually, the thermal power production from the solar collectors. An automation system is also designed and proposed for the realization of the newly introduced algorithm. The solar-combi system is computationally simulated, using annual time series of average hourly steps. A dimensioning optimization process is proposed, using as criterion the minimization of the thermal energy production levelized cost. The overall approach is validated on a school building with 1000 m2 of covered area, located in the hinterland of the island of Crete. It is seen that, given the high available solar radiation in the specific area, the proposed solar-combi system can guarantee the 100% annual heating load coverage of the examined building, with an annual contribution from the solar collectors higher than 45%. The annually average thermal power production levelized cost is calculated at 0.15 €/kWhth.

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The evacuated tube solar collector assisted heat pump for heating greenhouses

Cited by 84 publications

References 32 publications

Performance Evaluation of Root Zone Heating System Developed with Sustainable Materials for Application in Low Temperatures

Performance Evaluation of Root Zone Heating System Developed with Sustainable Materials for Application in Low Temperatures

Design of an innovative PV/T and heat pump system for greenhouse heating

Optimized Dimensioning and Operation Automation for a Solar-Combi System for Indoor Space Heating. A Case Study for a School Building in Crete

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