The Performance Improvements of a Ground-Coupled Heat Pump System for both Building Heating and Cooling Modes

2011 ◽  
Vol 354-355 ◽  
pp. 807-810 ◽  
Author(s):  
Zi Shu Qi ◽  
Qing Gao ◽  
Yan Liu ◽  
Y.Y. Yan ◽  
Jeffrey D. Spitler
Keyword(s):  
Heat Pump ◽  
Temperature Response ◽  
Energy Performance ◽  
Coefficient Of Performance ◽  
Fluid Temperature ◽  
Time Step ◽  
Pump System ◽  
Heating And Cooling ◽  
Ground Coupled Heat Pump ◽  
Cooling Loads

The objective of the paper is to describe the performance of ground-coupled heat pump (GCHP) system in 20 years. A mathematical model for simulation of GCHP system is built based on long time-step Eskilson’s theory. The design methodology is based on a simulation that predicts the temperature response of the ground heat exchanger (GHE) to monthly heating and cooling loads and monthly peak heating and cooling demands over a number of years. The temperature response also has a secondary impact on the predicted energy consumption of the system, as the coefficient of performance (COP) of the heat pump varies with entering fluid temperature. This paper presents GCHP system can achieve better energy performance in building that heating and cooling loads are balanced all the year round. It is illustrated by performing a GHE for a 300 m2 building located in Changchun, China.

Analysis and Research on the Performance of the Ground Source Heat Pump System in Different Areas of China

2011 ◽  
Vol 148-149 ◽  
pp. 1137-1140 ◽  
Author(s):  
Zi Shu Qi ◽  
Qing Gao ◽  
Yan Liu ◽  
Y.Y. Yan ◽  
Jeffrey D. Spitler
Keyword(s):  
Heat Exchanger ◽  
Heat Pump ◽  
Fluid Temperature ◽  
Ground Heat Exchanger ◽  
Ground Source Heat Pump ◽  
Time Step ◽  
Heating And Cooling ◽  
Ground Source ◽  
Vertical Ground ◽  
Cooling Loads

In the paper, it is to describe the performance of the vertical ground heat exchangers (GHE) in different areas of China. The energy consumption of ground source heat pump (GSHP) system is based on the instantaneous fluid temperature at the heat pump inlet. This temperature defines the GSHP coefficient of performance and hence the electricity consumption required in order to fulfill the energy demands of the building. A mathematical model for simulation of vertical ground heat exchanger system is built based on long time-step theory. The design methodology is based on a simulation that predicts the temperature response of the ground heat exchanger to hourly heating and cooling loads demand in 20 years. This paper presents GSHP system can achieve energy performance in buildings that heating and cooling loads all the year round in different areas.

scholarly journals Life cycle cost analysis of different residential heat pump systems

2020 ◽  
Vol 207 ◽  
pp. 01014
Author(s):  
Nadezhda Doseva ◽  
Daniela Chakyrova
Keyword(s):  
Energy Efficiency ◽  
Life Cycle ◽  
Heat Pump ◽  
Life Cycle Cost ◽  
Residential Buildings ◽  
Energy Performance ◽  
Coefficient Of Performance ◽  
Pump System ◽  
Heat Pump System ◽  
Heating And Cooling

Nowadays, the application of air-source heat pumps for heating and cooling in residential buildings has been increased significantly. The main occasion for this is the accessibility of a heat source for these devices - the external air. Nevertheless, the increase of the energy efficiency of the air source heat pump systems is a difficult design problem because their capacity and performance are a function of the dynamically changing parameters of the outdoor air. Because of that, the main aim of this study is to develop an approach for choosing a structural scheme of an air-to-water heat pump system under specific climatic conditions. The considered systems are monovalent, bivalent-parallel and bivalent-alternative heat pump systems. In the current paper is conducted a dynamic energy modeling of heating and cooling demand of a typical residential building situated in Varna, Bulgaria and applying the bin temperature data. It is assessed the effect of the heat pump capacity over the annual and seasonal energy performance of the heat pump systems. It is established the effect of the bivalent temperature, cut-off temperature and on-off cycles duration on rates of the criteria for techno-economic assessment. The seasonal coefficient of performance (SCOP), seasonal energy efficiency rate (SEER) and life cycle costs (LCC) of the analyzed heat pump systems are adopted as assessment parameters.

Experimental Study of Heating-Cooling Combined Ground Source Heat Pump System with Horizontal Ground Heat Exchanger

2011 ◽  
Vol 374-377 ◽  
pp. 398-404 ◽  
Author(s):  
Ying Ning Hu ◽  
Ban Jun Peng ◽  
Shan Shan Hu ◽  
Jun Lin
Keyword(s):  
Heat Exchanger ◽  
Heat Exchange ◽  
Heat Pump ◽  
Hot Water ◽  
Coefficient Of Performance ◽  
Ground Heat Exchanger ◽  
Pipe Length ◽  
Pump System ◽  
Heat Pump System ◽  
Heating And Cooling

A hot-water and air-conditioning (HWAC) combined ground sourse heat pump(GSHP) system with horizontal ground heat exchanger self-designed and actualized was presented in this paper. The heat transfer performance for the heat exchanger of two different pipe arrangements, three layers and four layers, respectively, was compared. It showed that the heat exchange quantity per pipe length for the pipe arrangement of three layers and four layers are 18.0 W/m and 15.0 W/m. The coefficient of performance (COP) of unit and system could remain 4.8 and 4.2 as GSHP system for heating water, and the COP of heating and cooling combination are up to 8.5 and 7.5, respectively. The power consumption of hot-water in a whole year is 9.0 kwh/t. The economy and feasibility analysis on vertical and horizontal ground heat exchanger were made, which showed that the investment cost per heat exchange quantity of horizontal ground heat exchanger is 51.4% lower than that of the vertical ground heat exchanger, but the occupied area of the former is 7 times larger than the latter's.

scholarly journals A Comparative Energy and Economic Analysis between a Low Enthalpy Geothermal Design and Gas, Diesel and Biomass Technologies for a HVAC System Installed in an Office Building

Energies ◽  
2019 ◽  
Vol 12 (5) ◽  
pp. 870 ◽  
Author(s):  
José Villarino ◽  
Alberto Villarino ◽  
I. de Arteaga ◽  
Roberto Quinteros ◽  
Alejandro Alañón
Keyword(s):  
Heat Pump ◽  
Economic Cost ◽  
Operating Conditions ◽  
Office Building ◽  
Geothermal System ◽  
Environmental Aspects ◽  
Pump System ◽  
Heat Pump System ◽  
Heating And Cooling ◽  
Ground Coupled Heat Pump

This paper presents an analysis of economic and energy between a ground-coupled heat pump system and other available technologies, such as natural gas, biomass, and diesel, providing heating, ventilation, and air conditioning to an office building. All the proposed systems are capable of reaching temperatures of 22 °C/25 °C in heating and cooling modes. EnergyPlus software was used to develop a simulation model and carry out the validation process. The first objective of the paper is the validation of the numerical model developed in EnergyPlus with the experimental results collected from the monitored building to evaluate the system in other operating conditions and to compare it with other available technologies. The second aim of the study is the assessment of the position of the low enthalpy geothermal system proposed versus the rest of the systems, from energy, economic, and environmental aspects. In addition, the annual heating and cooling seasonal energy efficiency ratio (COPsys) of the ground-coupled heat pump (GCHP) shown is higher than the others. The economic results determine a period between 6 and 9 years for the proposed GCHP system to have lower economic cost than the rest of the systems. The results obtained determine that the GCHP proposed system can satisfy the thermal demand in heating and cooling conditions, with optimal environmental values and economic viability.

Simulation of Solar Assisted Ground Source Heat Pump System in Different Regions

2011 ◽  
Vol 354-355 ◽  
pp. 798-801
Author(s):  
Qin Tao Zhou ◽  
Hua Dong ◽  
En Ze Zhou ◽  
Wei Yi
Keyword(s):  
Heat Pump ◽  
Storage Temperature ◽  
Weather Data ◽  
Fluid Temperature ◽  
Ground Source Heat Pump ◽  
Time Step ◽  
Pump System ◽  
Heat Pump System ◽  
Ground Source ◽  
Ground Loop

This study presents a simulation approach to assess the viability of solar assisted ground source heat pump system in different regions of China. A short time step model of ground loop exchanger is employed in the simulation with a 30% solar fraction. Weather data files used in the simulation are created based on Chinese Typical Year Weather (CTYW) data. Borehole length is optimized with a safety stop temperature of 0°C. The minimum Entering Fluid Temperature (EFT) decreases 1.3°C after 20-year simulation time and the team effect of ground loop exchangers is weaken as a result of spontaneous recovery of storage temperature. Borehole length replaced by area of solar collector ranges from 3.9m to 2.5m in the six cities. The results show that the annual performance of ground loop exchanger is low in heating-dominated regions and a solar assisted ground source heat pump (SAGSHP) system is needed in order to improve the system performance.

Photovoltaic thermal collector assisted heat pumps using environment-friendly working fluids

2020 ◽  
pp. 095440892094736
Author(s):  
AA Ammar ◽  
K Sopian ◽  
M Mohanraj
Keyword(s):  
Heat Pump ◽  
Energy Performance ◽  
Heat Pumps ◽  
Payback Period ◽  
Photovoltaic System ◽  
Coefficient Of Performance ◽  
Photovoltaic Module ◽  
Pump System ◽  
Heat Pump System ◽  
Thermal Evaporator

In this research, a photovoltaic-thermal collector assisted heat pump has been developed and tested its performance under the tropical climatic conditions of Malaysia. The refrigerants such as, R134a and R1234yf were selected based on its thermodynamic and thermo-physical properties. The temperature of the photovoltaic module was theoretically predicted under the influence of tube diameter, tube spacing and refrigerant mass flow rate. Further, the energy performance of the photovoltaic-thermal evaporator and the heat pump system are investigated experimentally. Finally, the economical feasibility of the photovoltaic-thermal collector evaporator was assessed for the period of 20 years. The results showed that, the tube spacing and diameter of the copper tubes used in the photovoltaic-thermal evaporator/collector using R134a and R1234yf were optimized to 80 mm and 12.7 mm, respectively. It was observed that, during the clear sunny day, the average photovoltaic module temperature was reduced to 30.9 °C under the influence of panel cooling using refrigerant. The output of the panel was enhanced by 21%–44% with increase in solar radiation from 400 W/m2 to 1000 W/m2. The coefficient of performance of the heat pump was varied from 4.8 to 6.84 with an average coefficient of performance of 5.8 during clear sunny days. The life cycle economic analysis indicated that, the photovoltaic-thermal collector evaporator assisted heat pump has a payback period of 3 years, whereas the reference photovoltaic system has a payback period of 8 years.

scholarly journals Hybridization of Heat Pump Systems With Natural Ventilation To Improve Energy Efficiency in Cooling Dominated Buildings

2021 ◽  
Vol 6 ◽  
pp. 33
Author(s):  
Nuno R. Martins ◽  
Peter J. Bourne-Webb
Keyword(s):  
Heat Pump ◽  
Natural Ventilation ◽  
Energy Performance ◽  
Ground Temperature ◽  
Improve Energy Efficiency ◽  
Final Energy ◽  
Heating And Cooling ◽  
Energy Needs ◽  
Energy Simulations ◽  
Cooling Loads

Building foundation piles can be used as heat exchangers in ground-source heat pump (GSHP) systems to provide highly efficient renewable heating and cooling (H&C). Unbalanced H&C loads lead to heat build-up in the ground, decreasing the system's overall performance. In this study, the introduction of natural ventilation (NV) has been examined to decrease cooling load imbalance in cooling-dominated buildings to improve system efficiency. Building energy simulations estimated the H&C loads for an office building in three Portuguese cities: Lisbon, Porto and Faro, yielding heating loads of 0.2–3.6 MWh/year and cooling loads of 260–450 MWh/year. Four renewable H&C technology scenarios were used to assess energy performance: (1) an air-source heat pump (ASHP) system; (2) a GSHP system utilizing energy piles; (3) hybrid ASHP-NV and (4) hybrid GSHP-NV. Over 50 years of operation, in Scenario (1) COP values of 2.45–2.55 (heating) and 3.62–4.15 (cooling) were obtained. In (2), COP values increased to 4.15–4.34 (heating) but fell to 3.36–3.79 (cooling), which increased annual final energy needs by 7–8%. Unbalanced cooling loads increased the ground temperature by 21–24 °C, which is unlikely to be acceptable. Compared to (1), introducing NV reduced cooling loads by 65–90% in Scenarios (3) and (4), with the final energy needs decreasing by 59–80% and 62–88%, respectively. A further benefit of the GSHP-NV hybrid is that the ground temperature increase was limited to 8‑12 °C. For cooling, the COP in (3) decreased compared to (1) (3.14–3.69), while in (4), COP improved to 3.45–6.10. This study concludes that hybrid GSHP-NV systems should be considered in some cooling-dominated scenarios.

Experimental studies on direct expansion solar thermal heat pump systems using R430A as a substitute to R134a

2021 ◽  
pp. 095440892110209
Author(s):  
M Mohanraj ◽  
I M Kartheheyan
Keyword(s):  
Global Warming ◽  
Energy Consumption ◽  
Heat Pump ◽  
Energy Performance ◽  
Solar Thermal ◽  
Coefficient Of Performance ◽  
Direct Expansion ◽  
Pump System ◽  
Discharge Temperature ◽  
Heating Capacity

The use of halogen-based refrigerants in heat pump applications is restricted because of their high global warming potential (GWP). Therefore, it is necessary to identify a low GWP substitute for heat pump applications. This article presents the energy performance of a direct expansion solar thermal heat pump system (DXSTHPS) using R430A as an environmentally friendly substitute to phase out R134a. The effects of ambient parameters on compressor discharge temperature, compressor energy consumption, condenser heating capacity and coefficient of performance (COP) of a DXSTHPS using R134a and R430A are estimated and compared. Moreover, the total equivalent global warming impacts (TEGWI) of a DXSTHPS using R134a and R430A are evaluated. The results showed that the R430A has 0.7–1.9% lower compressor energy consumption than R134a. The condenser heating capacity and COP of a DXSTHPS using R430A are higher than R134a by 4.6–8.7% and 5.1–10.2%, respectively. The compressor discharge temperature observed in a DXSTHPS using R430A is 5.8 °C higher than R134a. The lubricant physical properties are retained at higher compressor operating temperatures, ensuring compressor reliability. The DXSTHPS using R430A has 4.2–12.9% lower TEGWI due to its lower GWP with lower compressor energy consumption than R134a.

Dynamic Analysis of a Dual-Mode CO2 Heat Pump With Both Hot and Cold Thermal Storage

2013 ◽  
Author(s):  
Lars Houbak-Jensen ◽  
Anders Holten ◽  
Morten Boje Blarke ◽  
Eckhard A. Groll ◽  
Ali Shakouri ◽  
...  
Keyword(s):  
Differential Equations ◽  
Heat Pump ◽  
Cold Storage ◽  
Coefficient Of Performance ◽  
Computational Time ◽  
Extended Model ◽  
Algebraic Differential Equation ◽  
Spatial Discretization ◽  
Pump System ◽  
Heating And Cooling

We investigated the dynamics of a transcritical CO2 heat pump system including hot and cold thermal storages, which makes up the concept “thermal battery”. The analytical model is used for the study of the dynamics of the system involving simultaneous supply of heating and cooling for buildings. The model includes the dynamics of the gas cooler, evaporator and the thermal storages, while the compressor and the expansion valve are considered quasi-static. The heat transfer in the dynamically modeled components is described by partial differential equations (PDEs) consisting of heat conduction, convection, and source terms. Each component is divided into a number of volumes adjusted according to the required precision and reasonable computational time. We applied two discretization schemes in order to find a numerical solution to the PDEs. The spatial discretization for the heat exchangers is performed by using the upwind scheme, where the fluid properties are individually calculated within each volume. Due to the discrete events in form of tapping and loading (or charging and discharging) of the heat storages, the discretization approach takes into account the sharp spatial transitions within the thermal storages. Therefore, the method of lines in combination with the Superbee slope-limiter was applied for the spatial discretization for high resolution calculation. The modeling approach results in a set of algebraic and ordinary differential equations (ODEs), hence the model becomes an algebraic differential equation problem, which we solved by using MATLAB solver ODE15s. This extended model was used to simulate a dynamic response of the case with varying heating and cooling consumption over a period of 24 hours in a building. The heating and cooling energy consumption follow a sinusoidal and continuous pattern. The results include the effect on both the outlet temperatures and the system coefficient-of-performance (COP). The outlet energy from the hot storage and the cold storage is used for heating tap water and a chilled water space cooling application subject to temperature requirements. Dimensioning of both storages is crucial for obtaining the required temperatures. The model identifies the critical storage levels required to satisfy the periodic but out-of-phase combination of heating and cooling demands. The volume of the cold storage will have to be considerably larger than the hot storage due to the lower temperature difference.

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