Performance analysis of a rooftop, air-to-air heat pump working with CO 2

Calabrese, Nicolandrea; Mastrullo, R.; Mauro, A.W.; Rovella, Paola; Tammaro, Marcello

doi:10.1016/j.applthermaleng.2014.10.057

Cited by 21 publications

(4 citation statements)

References 19 publications

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“…In this regard, Calabrese et al [9] studied an air-to-air CO 2 heat pump with IHX, confirming that the best COP values are obtained in low-temperature working conditions. For a CO 2 refrigeration system, Chen and Gu [10] provided a new expression for the effectiveness of the heat exchanger and studied by means of simulations the influence of IHX effectiveness and the ambient temperature, as well as the IHX inlet quality in the optimal operating pressure.…”

Section: Introductionmentioning

confidence: 81%

“…Exploring a different option, Aranguren et al [7] used thermoelectric subcooler, achieving an experimental COP improvement of 11.3 % and increasing the cooling capacity in a refrigeration cycle. Finally, an option that arouses great interest is the addition of an Internal Heat Exchanger (IHX), which uses the refrigerant at the evaporator outlet for subcooling at the gas cooler outlet, achieving a pressure drop in the system [8][9][10][11][12][13].…”

Section: Introductionmentioning

confidence: 99%

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Impact of an internal heat exchanger on a transcritical CO2 heat pump under optimal pressure conditions

Otón-Martínez

Illán-Gómez

García-Cascales

et al. 2022

Applied Thermal Engineering

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Section: Introductionmentioning

confidence: 81%

Section: Introductionmentioning

confidence: 99%

Impact of an internal heat exchanger on a transcritical CO2 heat pump under optimal pressure conditions

Otón-Martínez

Illán-Gómez

García-Cascales

et al. 2022

Applied Thermal Engineering

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“…This fact makes R134a a significant threat for the environment. In order to eliminate this refrigerant application, Calabrese et al (2015) explored the suitable operating condition shown in Figure 2-4 for applying roof top air to air system working with trans-critical carbon dioxide cycle during the heating season. Based on the experimental results which was set up in Rome, Italy, the heating power and the COP are affected by the air temperature at the gas cooler inlet as well as part load working conditions.…”

Section: Air To Airmentioning

confidence: 99%

Heat Pump Water Heater For Cold Climate – Canada

Amirirad¹

2021

Preprint

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Considering the large energy consumption of conventional water heaters in residential buildings, the performance of a new type of water heater has been characterized through conducting experiments and numerical modelling. The specific water heater investigated in this work benefits from heat absorption from the indoor air, denoted as the air source heat pump water heater (ASHPWH), and is located in the Archetype Sustainable Twin House B in Toronto. The experiments have been conducted under three different indoor conditions associated with temperature and humidity. The coefficient of performance (COP), which quantifies the ratio of heating capacity to the consumed power of ASHPWH, ranges between 1.5 and 5, depending on the indoor dry bulb and water inlet temperatures. A TRNSYS model of ASHPWH has been constructed based on the obtained experimental results and has subsequently been integrated with a TRNSYS model of the Archetype Sustainable House (ASH). The numerical results were verified with the experimental data. The model results suggests that after employing ASHPWH, the domestic hot water energy consumption reduces by 60.3% and 53.2% compared to the electric water heater in summer and winter respectively. Due to the energy absorption of ASHPWH from the indoor environment, the heating load of the ASH house increases while its cooling load decreases. Furthermore, the annual electricity consumption of the ASH house due to the required heating and cooling as well as the domestic hot water demand is reduced by 21.3%. Finally, as a consequence of employing ASHPWH, the energy cost and GHG emission were reduced respectively by 22% and 21.7%. By investigating the system in four other Canadian cities, it appears that Vancouver and Edmonton would have the maximum and minimum energy savings respectively.

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“…Although CO2 vapor compression heat pumps are widely adopted in heating/cooling applications, the high temperature of the discharge and return from the consumer significantly reduce the performance. Previous studies have addressed the performance of CO2 HP-based hot water production systems, considering both experimental and numerical approaches [16,17].…”

Section: Introductionmentioning

confidence: 99%

Energy and Economic Assessment of Energy Efficiency Options for Energy Districts: Case Studies in Italy and Egypt

et al. 2021

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In this research, a technoeconomic comparison of energy efficiency options for energy districts located in different climatic areas (Naples, Italy and Fayoum, Egypt) is presented. A dynamic simulation model based on TRNSYS is developed to evaluate the different energy efficiency options, which includes different buildings of conceived districts. The TRNSYS model is integrated with the plug-in Google SketchUp TRNSYS3d to estimate the thermal load of the buildings and the temporal variation. The model considers the unsteady state energy balance and includes all the features of the building’s envelope. For the considered climatic zones and for the different energy efficiency measures, primary energy savings, pay back periods and reduced CO2 emissions are evaluated. The proposed energy efficiency options include a district heating system for hot water supply, air-to-air conventional heat pumps for both cooling and space heating of the buildings and the integration of photovoltaic and solar thermal systems. The energy actions are compared to baseline scenarios, where the hot water and space heating demand is satisfied by conventional natural gas boilers, the cooling demand is met by conventional air-to-air vapor compression heat pumps and the electric energy demand is satisfied by the power grid. The simulation results provide valuable guidance for selecting the optimal designs and system configurations, as well as suggest guidelines to policymakers to define decarbonization targets in different scenarios. The scenario of Fayoum offers a savings of 67% in primary energy, but the associated payback period extends to 23 years due to the lower cost of energy in comparison to Naples.

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Performance analysis of a rooftop, air-to-air heat pump working with CO 2

Cited by 21 publications

References 19 publications

Impact of an internal heat exchanger on a transcritical CO2 heat pump under optimal pressure conditions

Impact of an internal heat exchanger on a transcritical CO2 heat pump under optimal pressure conditions

Heat Pump Water Heater For Cold Climate – Canada

Energy and Economic Assessment of Energy Efficiency Options for Energy Districts: Case Studies in Italy and Egypt

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