Feasibility of solar-geothermal hybrid source heat pump for producing domestic hot water in hot climates

Paulino

J. Solar Eneg. Res. Updat.

et al. 2023

Self Cite

This paper presents the development of a mathematical model for a direct-expansion solar-assisted heat pump (DX-SAHP) operating in steady-state. The mathematical model was implemented using the scientific software EES and using a code written in Python. It was utilized a lumped parameter model for the heat exchangers and a semi-empirical model for the compressor. The mathematical model was validated using experimental data of a DX-SAHP running with R134a. Two hundred simulations were made combining different correlations for estimating the convective heat transfer coefficient in the evaporator/collector. The Mean Absolute Deviation (MAD) and the Mean Deviation (MD) between the theoretical and experimental values for the COP were 2.6±1.8 % and 0.9±1.8 %, respectively. The MAD and MD between the discharge temperature were 1.56±0.16 % and -1.45±0.16 %. The mean difference between the results using EES and Python were 1.4 %. The use of Python with parallel computing for uncertainty analyses, reduced the simulation time in 88 % if compared with EES. The model in Python is available as open-source through the platform Google Colaboratory.

Section: Compressor Modelmentioning

confidence: 99%

Experimental Validation Through a Parallel Computation Algorithm for Evaluation Uncertainty of the Mathematical Model of Direct Expansion Solar Assisted Heat Pump

Paulino

J. Solar Eneg. Res. Updat.

et al. 2023

Self Cite

“…Jonas et al [26] have found that the incorporation of solar thermal collectors with a ground or air-source heat pump can improve the system's performance. Duarte et al [27] conducted a comparative study regarding domestic hot water for different heat pump heating systems. They have found that the hybrid design that combines solar and ground sources is more efficient compared to the one-source design with only solar or ground or air sources.…”

Section: Introductionmentioning

confidence: 99%

Dynamic Energy Analysis of Different Heat Pump Heating Systems Exploiting Renewable Energy Sources

et al. 2023

Renewable energy source-fed heat pumps (HPs) may perform up to very high-efficiency standards, offering a promising tool in the wider residential heat decarbonization effort. In this context, this paper investigates different heating configurations utilizing various renewable thermal sources in conjunction with an HP-based system in order to determine the optimal configuration in terms of efficiency, using an existing, fully functioning residential building in Zaragoza, Spain, as our case study, comprising 40 dwellings. Four different HP configurations are investigated:, (i) an air-source system, (ii) a ground-source system, (iii) a dual-source system with solar thermal collectors, and (iv) a triple-source system based on solar, geothermal, and ambient sources. For the purpose of such investigation, detailed dynamic energy simulations are conducted through the use of the INTEMA.building tool (developed in Modelica), applying a multi-objective optimization process that aims at minimizing both the annual electricity consumption and the net present cost. It is demonstrated that the renewable thermally driven HPs are more efficient than the conventional, air-source ones, with the seasonal coefficient of performance increasing by 9.98% (ground source), 4.57% (dual source), and 17.40% (triple source), compared to the air-source heat pump system. Finally, it is revealed (via integrated techno-economic analyses) that the most effective and economical design is the dual source system, while the most expensive is the ground-source configuration. These findings can guide the ongoing design efforts on green residential heat solutions at both research and commercial implementation level.

Proceedings of the 3rd International Conference on Advances in Energy Research and Applications (ICAERA'23)

“…They ignored thermal recovery of soil around the earth air exchanger and thus, their work was valid only for short time periods. Duarte et al [5] studied a series connection of a ground water aquifer and a solar collector under Brazilian climate. Using lumped modelling method, a thermal as well as economic analysis was carried.…”

Section: Introductionmentioning

confidence: 99%

Transient Analysis of Lower and Ground Zone Energy Extraction in Solar Ponds with Temperature Drop across Exchangers

Verma¹,

Das²

2022

Solar ponds involve energy extraction generally from their lower convective zone. Sometimes, energy is extracted from ground below them too, in order to enhance the output. A transient model is presented that studies such a pond system. The novelty lies in the fact that temperature drop across exchanger surfaces in the two zones are included into the relevant equations, which has not been considered in earlier transient models. A transient analysis for a one-year period under the climatic conditions of Copiapo, Chile has been carried. The finite difference method has been used to solve the relevant equations via a MATLAB code. The model is successfully validated with a simpler version available in the literature. It has been shown that not considering this effect leads to a significant overestimation of the performance. A maximum error of about 13% is seen in the value of outlet temperature of the extracted water stream. Further, it is observed that exchanger pipes in the ground should be of as little cross section as possible. It is also seen that places where year average ambient temperature ground isotherm is deeper prove more productive for such pond systems. Finally, it is observed that mass flux corresponding to ground energy extraction should be low from outlet temperature point of view but should be higher from outgoing energy perspective.