Experimental Research on a Novel Solution Regeneration System for Heat Source Tower Based on Vacuum Boiling and Condensation

Wen, Xiantai; Cao, Xianqi; Yu, Pengfei; Yu, Jin-Won

doi:10.30919/esee8c175

Cited by 7 publications

(4 citation statements)

References 11 publications

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“…Moreover, Li et al [85] proposed a low-pressure boiling solution regeneration method. Wen et al [86,87] also proposed a solution regeneration system for the HST based on vacuum boiling and condensation. With the increase in the solution concentration, the regeneration efficiency and regeneration rate first increase and then decrease.…”

Section: Research On the Antifreeze Solution Of Hsthpsmentioning

confidence: 99%

A Review on the Heat-Source Tower Heat Pump Systems in China

Yao,

Feng,

2024

Energies

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Based on air-, water-, and ground-source heat pump systems, a novel type of heat pump system, named the heat-source tower heat pump system (HSTHPS), has recently been developed in the southern area of China. The HSTHPS overcomes the evaporator frosting problems of the air-source heat pump system (ASHPS) when the ambient temperature is lower, and it avoids the geological condition constraints of the water- and ground-source heat pump systems. However, studies on the HSTHPS are insufficient, thereby limiting its development and applications. Thus, the present review provides a detailed literature review on the advancements of HSTHPSs in China, including the HSTHPS operation principle, heat-source tower (HST) structure, heat and mass transfer characteristics, HSTHPS performance, antifreeze solution use, and antifreeze solution regeneration. Studies on the heat and mass transfer characteristics of HSTs are sufficient for guiding the application. Regarding open systems, the solution drifting to the air needs to resolved, and future studies need to focus on structure optimization for heat exchangers in closed systems. Moreover, advanced defrosting technology should be applied to closed-type HSTs, and a suitable operation strategy for HSTHPSs should be developed. Future priorities should involve integrating HSTHPSs with additional renewable energy in order to achieve continuous, stable, and efficient heating in winter based on the characteristics of local climate and renewable energy.

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Section: Research On the Antifreeze Solution Of Hsthpsmentioning

confidence: 99%

A Review on the Heat-Source Tower Heat Pump Systems in China

Yao,

Feng,

2024

Energies

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“…This regeneration device is independent from the HTHP system, and the power used by it is to satisfy the gasification latent heat of water. Therefore, the regeneration device power has no influence on the heating capacity of the HTHP system [21,22].…”

Section: System Descriptionmentioning

confidence: 99%

Model-based optimal operation of heating tower heat pump systems

Huang

Zhang

et al. 2019

Building and Environment

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In current applications of heating tower heat pumps (HTHPs), the systems tend to run with constant speed or fixed set points, which can be inefficient under varying weather data and building loads. To address this issue, this study proposes a model-based optimal operation of the HTHPs to achieve energy savings in both cooling and heating modes. Firstly, a physics-based model for an existing HTHP system was developed. Then, artificial neural network (ANN) models were developed and trained with vast amount of operational data generated by the physics-based model. The ANN models were found to be highly accurate (average relative error less than 1%) and computationally efficient (about 300 times faster than the physics-based model). After that, three optimal approaches were proposed to minimize the total energy consumption of the HTHP system. Approach 1 optimizes the load distribution between different heat pump units. Approach 2 optimizes the speed of fans and pumps by fixed approach and range of the condenser water (or evaporator solution). Approach 3 optimizes both the load distribution and the speed of fans and pumps. The optimization is implemented by using the ANN models, proposed approaches, and a genetic algorithm via a case study. The results show that the energy savings in the cooling season are 2.7%, 11.4%, and 14.8% by the three approaches, respectively. In the heating season, the energy savings of the three approaches are 1.6%, -1.4%, and 4.7%, respectively. Moreover, the thermodynamic performance in typical days was analyzed to investigate how energy savings could be achieved.

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“…Song et al (2019) conducted an experimental investigation to figure out the heat and mass transfer characteristics of a cross-flow closed-type heating tower, and the correlations of heat and mass transfer coefficients for heat tower were developed. Aiming at the problem of moisture absorption in heating tower in winter, Wen et al (2018Wen et al ( , 2019 proposed and studied a new type of anti-freezing solution regeneration system based on vacuum boiling.…”

Section: Introductionmentioning

confidence: 99%

“…Aiming at the problem of moisture absorption in heating tower in winter, Wen et al. (2018, 2019) proposed and studied a new type of anti-freezing solution regeneration system based on vacuum boiling.…”

Section: Introductionmentioning

confidence: 99%

Effects of the operation parameters of a closed-type heating tower on the performance of heating tower heat pump system

Feng

Zhao

et al. 2020

Energy Exploration & Exploitation

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The ventilator of the heating tower and the circulating pump of the anti-freeze solution are the main electrical equipment of a heating tower heat pump system, besides the compressor. By controlling the working frequencies of the ventilator of the heating tower and circulating pump of the anti-freeze solution, the effects of the operation parameters of a closed-type heating tower on its heat absorption and the performance of heating tower heat pump system were investigated under winter heat conditions. The results indicated that reducing the frequency of the circulating pump for the anti-freeze solution leads to a decrease in the temperature of the outlet evaporator of the anti-freezing solution and an increased temperature difference between the anti-freeze solution flowing into and out of the heating tower; meanwhile, excessively high and low anti-freeze flow rates lead to reduced heat absorption of the closed-type heating tower. The coefficient of performance fluctuates slightly if the frequency of circulating pump is above 20 Hz, but a slight drop in coefficient of performance is observed when the frequency is less than 15 Hz. The system energy efficiency ratio tends to increase as the frequency of circulating pump is reduced, although a substantial reduction occurs at 10 Hz. Furthermore, a reduced ventilator frequency decreases the temperatures of the anti-freeze solution at the inlet and outlet of the heating tower and the temperature difference, hindering the heat absorption of the heating tower. With reductions in the ventilator frequency, the coefficient of performance exhibits an initial increase followed by subsequent decreases, while the system energy efficiency ratio showed continual increases until the ventilator frequency dropped to 10 Hz. When the ventilator frequency or circulating pump frequency drops to 15 Hz and 10 Hz, the evaporation temperature of the heat pump unit decreases, resulting in an excessively exhaust temperature, which is not favorable for the safe operation of the system.

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Experimental Research on a Novel Solution Regeneration System for Heat Source Tower Based on Vacuum Boiling and Condensation

Cited by 7 publications

References 11 publications

A Review on the Heat-Source Tower Heat Pump Systems in China

A Review on the Heat-Source Tower Heat Pump Systems in China

Model-based optimal operation of heating tower heat pump systems

Effects of the operation parameters of a closed-type heating tower on the performance of heating tower heat pump system

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