Dynamic model and experimental validation for a gas cooler of a CO
            <sub>2</sub>
            heat pump for heating residential water

Oliveira, Raphael Nunes de; Faria, Ralney; Antoñanzas-Torres, F.; Machado, Luiz; Koury, R.N.N.

doi:10.1080/23744731.2015.1070647

Cited by 11 publications

(5 citation statements)

References 15 publications

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“…The prototype used in this study was previously presented by Faria et al [21] and by Oliveira et al [20]. In this study, the equipment needs to produce hot water for a family of four people.…”

Section: Prototype Descriptionmentioning

confidence: 99%

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Dynamic Model of a Transcritical CO2 Heat Pump for Residential Water Heating

et al. 2021

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This paper presents a distributed mathematical model for a carbon dioxide direct expansion solar-assisted heat pump used to heat bath water. The main components are a gas cooler, a needle valve, an evaporator/collector, and a compressor. To develop the heat exchange models, mass, energy, and momentum balances were used. The model was validated for transient as well as steady state conditions using experimental data. A reasonably good agreement was observed between the predicted temperatures and experimental data. The simulations showed that the time step required to demonstrate the behavior of the heat pump in the transient regime is greater than the time step required for the steady state. The results obtained with the mathematical model revealed that a reduction in the water mass flow rate results in an increase in the water outlet temperature. In addition, when the carbon dioxide mass flow rate is reduced, the compressor inlet and outlet temperatures increase as well as the water outlet temperature.

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Section: Prototype Descriptionmentioning

confidence: 99%

“…The use of the CO 2 in a DX-SAHP was recently reported in the literature by Oliveira et al [20], who developed a distributed mathematical model to study the transient condition in the gas cooler of a CO 2 DX-SAHP. That mathematical model was validated using experimental data.…”

Section: Introductionmentioning

confidence: 99%

Dynamic Model of a Transcritical CO2 Heat Pump for Residential Water Heating

et al. 2021

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“…Various studies using mathematical models for DX-SAHP were found in the literature. Most of them are complete models of the system, but some studies modeled partially the heat pump [10][11][12][13]. The studies using complete models of DX-SAHP are summarized in Table 1.…”

Section: Introductionmentioning

confidence: 99%

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

Duarte

Paulino

Duarte

et al. 2023

J. Solar Eneg. Res. Updat.

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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.

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“…Compared with solar collectors, air-source heat pumps have the merit of availability at any time and can provide relatively stable heat supply (Yu et al 2020;de Oliveira et al 2015).…”

Section: Introductionmentioning

confidence: 99%

A study on the integration of air-source heat pumps, solar collectors, and PCM tanks for outdoor swimming pools for winter application in subtropical climates

Nord

et al. 2020

Journal of Building Performance Simulation

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This study presents a new integration of air-source heat pumps, solar collectors and PCM tank regarding the dynamics of outdoor swimming pools, and investigates its application in outdoor swimming pools for extending their availability in winter season for subtropical climates. The proposed integration system harvests heat from both ambient air via air-source heat pumps and solar radiation via solar collectors. PCM tank are introduced to shift the electricity use from the on-peak to off-peak period in order to reduce the operating cost. Since multiple heat sources are used, two issues in the development are addressed: 1) main components sizing and 2) multicriterion design. The sizing problem is solved by considering the complementarity of different heating sources, while the multi-criterion design considers both the initial investment, thermal comfort, operating cost, and energy use. To illustrate the proposed main components sizing and multi-criterion design methods, a case study of using the heating system in a typical swimming pool in Hong Kong is conducted. Based on the proposed main component sizing method, the typical combinations of different solar collector area, air-source heat pump heating capacity, and PCM tank volume are determined using MATLAB codes. Based on the proposed multi-criterion design method, the results of the system operation simulated by TRNSYS and MATLAB in different cases are used to identify the optimal solar fraction. Thus, it can be 2 concluded that the proposed main components sizing, and multi-criterion design methods can well guide the design of the swimming pool heating system with multiple heat source.

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Dynamic model and experimental validation for a gas cooler of a CO ₂ heat pump for heating residential water

Cited by 11 publications

References 15 publications

Dynamic Model of a Transcritical CO2 Heat Pump for Residential Water Heating

Dynamic Model of a Transcritical CO2 Heat Pump for Residential Water Heating

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

A study on the integration of air-source heat pumps, solar collectors, and PCM tanks for outdoor swimming pools for winter application in subtropical climates

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Dynamic model and experimental validation for a gas cooler of a CO 2 heat pump for heating residential water

Cited by 11 publications

References 15 publications

Dynamic Model of a Transcritical CO2 Heat Pump for Residential Water Heating

Dynamic Model of a Transcritical CO2 Heat Pump for Residential Water Heating

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

A study on the integration of air-source heat pumps, solar collectors, and PCM tanks for outdoor swimming pools for winter application in subtropical climates

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Dynamic model and experimental validation for a gas cooler of a CO ₂ heat pump for heating residential water