Performance Optimization of Solar-Assisted Heat Pump System for Water Heating Applications

Chandan Swaroop Meena,Aritra Ghosh,Binju P Raj,Nehul Agarwal,Lohit Saini

doi:10.3390/en14123534

Abstract

The use of solar energy in water heating applications, such as in solar-assisted heat pump systems, has great benefits, such as reductions in heat transfer losses, control over incident solar heat, and generation of environmentally benign water heat. In the present study, we performed parametric optimization based on an experimental model of a solar-assisted heat pump system for water heating (SAHPSWH) in the context of colder climatic regions receiving minimal solar radiation. Various parameters were investigated, such as the different glazing arrangements, the distances between fluid-circulating tubes, and the absorber sheet arrangement. The results showed that double glazing was more efficient than single glazing, with average COP values of 3.37 and 2.69, respectively, and with similar heat gain rates. When the evaporator tube was soldered below the absorber plate, the COP was 1.19 times greater than when the tube was soldered above the absorber plate. We also analyzed whether the collector efficiency factor F′ has an inverse relationship with the tube distance and a direct relationship with the absorber plate thickness. Through this experimental study, we verified that the SAHPSWH is reliable if designed judiciously. This promising energy-saving system is particularly suitable for areas abundant in solar radiation, such as in India, where the needs for space conditioning and water heating are constant.

Highlights

To construct energy-efficient sustainable buildings in compliance with the emerging regulations for global warming and greenhouse gas (GHG) emissions, several changes are required [1,2]
The nomenclature for the absorber plate and tube used for the experimental study is shown in Figure 3, where Di is the internal diameter of the tube, Do is the external diameter of the tube, b represents the bond width between the serpentine tube and the absorber plate with thickness δ, and δt is the thickness of the serpentine tube used
The results showed that 30 L of water could be heated from 23 ◦ C to 50 ◦ C in 55 to 75 min when evaporator tubes were soldered above the absorber plate, with energy consumption rates of about 0.30 to 0.39 kWh and with Coefficient of Performance (COP) values varying between

Summary

Introduction

To construct energy-efficient sustainable buildings in compliance with the emerging regulations for global warming and greenhouse gas (GHG) emissions, several changes are required [1,2]. Applications based on solar thermal energy have gained massive attention from 19700 s onwards, following the beginning of the energy crisis [5]. The process of collecting solar arrays in the form of energy and converting them into useful heat for water heating, space conditioning, or agricultural or industrial applications is the basis of solar thermal applications [6]. Solar water heating accounts for a major proportion of all applications in the market; various technical flaws, such as uncertainty related to the heat gain efficiency and heat loss, act as barriers to its promotion [7]. The solar-assisted heat pump system for water heating (SAHPSWH) has advantages over conventional solar water heaters in terms of performance and initial investment, even under changing conditions and uneven weather. The conventional systems contain water as the working fluid, while hybrid water heating systems use a refrigerant as the working fluid, which transfers heat to the water [9]

Methods

Results

Conclusion