Energy Analysis and Optimization of a Water-Loop Heat Pump System

2010 ◽  
Vol 2 (2) ◽  
Author(s):  
Shui Yuan ◽  
Michel Grabon
Keyword(s):  
Water Temperature ◽  
Heat Pump ◽  
Energy Savings ◽  
Water Source ◽  
Energy Performance ◽  
Heat Pumps ◽  
Pump System ◽  
Heat Pump System ◽  
Heating And Cooling ◽  
The Impact

A water-loop heat pump system consists of a set of water-source heat pumps that are connected with a closed-loop water network, which allows heat to be injected into or extracted out of the loop water. Such a configuration is able to meet simultaneous heating and cooling demands with a heat recovery capability. This paper analyzes the impact of loop water temperature on energy performance of individual heat pumps and the whole system, demonstrates that there exists a unique loop water temperature that minimizes overall power consumption of the configuration under discussion, and proposes a strategy to find the optimal temperature, which can be implemented in a real-time application. Simulations have been conducted to verify that a significant energy savings can be achieved over conventional practice.

Analysis of Water Heat Pollution of Thermal Discharge in Surface Water Source Heat Pump System

2013 ◽  
Vol 368-370 ◽  
pp. 364-368
Author(s):  
Min Wang ◽  
Yue Jin Yu
Keyword(s):  
Surface Water ◽  
Water Temperature ◽  
Heat Pump ◽  
Preventive Measures ◽  
Water Source ◽  
Heat Pumps ◽  
Thermal Discharge ◽  
Pump System ◽  
Heat Pump System ◽  
Local Water

To comprehensively evaluate surface water source heat pump system, the problem of water heat pollution of thermal discharge in surface water source heat pump system should be seriously considered. This study summarizes the causes and hazards of water heat pollution of surface water source heat pump, explores the characteristics of water heat pollution of lake-source heat pump system, river-source heat pump system and sea-source heat pump system respectively, and proposes several preventive measures for solving the problem. Concludes that surface water heat pumps discharges can change local water temperature, and various types of water bodies have different degree of heat pollution.

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 Design and Analysis of a Distributed Water Heat Pump System for Near- and Net-Zero Energy Commercial Buildings

2021 ◽  
Author(s):  
Maudud Hassan Quazi
Keyword(s):  
Natural Gas ◽  
Heat Pump ◽  
Cooling Tower ◽  
Heat Pumps ◽  
Base Case ◽  
Hvac System ◽  
Pump System ◽  
Heat Pump System ◽  
Heating And Cooling ◽  
Net Zero

This objective of this project is to determine the energy and environmental potential of distributed common loop water source heat pump system in a near or net-zero commercial office building, which has simultaneous heating and cooling load in winter and shoulder seasons. It is expected that the perimeter zones will have heating demand during those months, while the core zones will have consistent cooling demand throughout the year. The motive is to reclaim the rejected heat from the cooling operation and transfer it to the zones requiring heating. The building under study is a 60,000 ft2 three storey commercial office building, which has private offices along the perimeter, and open work area in the core. In the first part of the analysis, the base building has been modelled and simulated to the minimum requirements of ASHRAE 90.1-Energy Standard for Buildings except Low-Rise Residential Buildings using simulation software eQuest 3.65. The Heating Ventilation and Airconditioning (HVAC) system used is four-pipe fan coil system serving individual zones. The fan coil units use a centralized natural gas boiler and a variable capacity centrifugal chiller as external source of heating and cooling respectively. The base case consumes a total of 524.54 x 1000 kWh of electricity and 1,056 million Btu of natural gas annually. The second part is the modelling and simulation of a proposed case, which uses the same building envelope, occupancy, lighting and equipment as the base case. The HVAC system used is a distributed common loop heat pump system connected to a cooling tower for heat rejection, and a condensing boiler for heat addition. During the occupied hours, when simultaneous cooling and heating loads exist in the building, the cooling zone heat pumps rejects exhaust heat into the common loop, and the heat is subsequently used by the heat pumps operating in heating mode. Using this method, the heat pump system reduces its dependence on the cooling tower and the boiler, which only operate to maintain the loop temperature in an acceptable range. There is 9,510 kWh (1.81%) increase in electricity consumption by proposed case comparing to the base building. Natural gas consumption has been reduced by 353.65 million Btu (33.48%). Annual utility bill has increased by $1,483.00 which is 1.88% higher than the base case. 15.7 tonnes of greenhouse gas can be reduced if the proposed case is adopted.

scholarly journals Heat Pump Heating System Development of Educational Building based on Energy, Economical and Environmental Impacts

2019 ◽  
Vol 63 (3) ◽  
pp. 207-213
Author(s):  
Miklós Kassai
Keyword(s):  
Heat Pump ◽  
Energy Savings ◽  
System Development ◽  
Heating System ◽  
Heat Pumps ◽  
The European Union ◽  
Pump System ◽  
Environmental Friendliness ◽  
Heat Pump System ◽  
Payback Time

In this research the technical designing of energy efficient heating system with vertical-borehole heat pumps for institutional buildings was performed. The local government would like to change the old gas boiler-based heat producing system to up-to-date, environmental friendly equipment with the financial support of the European Union. The payback time was calculated and environmental calculations were achieved with carbon dioxide saving by various conditions that were also achieved during the research project. The results show that the heat pump system also provides a significant reduction of environmental load, in addition to significant energy savings. The amount of calculated savings justifies the environmental friendliness of heat pump systems.

scholarly journals Design and Analysis of a Distributed Water Heat Pump System for Near- and Net-Zero Energy Commercial Buildings

2021 ◽  
Author(s):  
Maudud Hassan Quazi
Keyword(s):  
Natural Gas ◽  
Heat Pump ◽  
Cooling Tower ◽  
Heat Pumps ◽  
Base Case ◽  
Hvac System ◽  
Pump System ◽  
Heat Pump System ◽  
Heating And Cooling ◽  
Net Zero

This objective of this project is to determine the energy and environmental potential of distributed common loop water source heat pump system in a near or net-zero commercial office building, which has simultaneous heating and cooling load in winter and shoulder seasons. It is expected that the perimeter zones will have heating demand during those months, while the core zones will have consistent cooling demand throughout the year. The motive is to reclaim the rejected heat from the cooling operation and transfer it to the zones requiring heating. The building under study is a 60,000 ft2 three storey commercial office building, which has private offices along the perimeter, and open work area in the core. In the first part of the analysis, the base building has been modelled and simulated to the minimum requirements of ASHRAE 90.1-Energy Standard for Buildings except Low-Rise Residential Buildings using simulation software eQuest 3.65. The Heating Ventilation and Airconditioning (HVAC) system used is four-pipe fan coil system serving individual zones. The fan coil units use a centralized natural gas boiler and a variable capacity centrifugal chiller as external source of heating and cooling respectively. The base case consumes a total of 524.54 x 1000 kWh of electricity and 1,056 million Btu of natural gas annually. The second part is the modelling and simulation of a proposed case, which uses the same building envelope, occupancy, lighting and equipment as the base case. The HVAC system used is a distributed common loop heat pump system connected to a cooling tower for heat rejection, and a condensing boiler for heat addition. During the occupied hours, when simultaneous cooling and heating loads exist in the building, the cooling zone heat pumps rejects exhaust heat into the common loop, and the heat is subsequently used by the heat pumps operating in heating mode. Using this method, the heat pump system reduces its dependence on the cooling tower and the boiler, which only operate to maintain the loop temperature in an acceptable range. There is 9,510 kWh (1.81%) increase in electricity consumption by proposed case comparing to the base building. Natural gas consumption has been reduced by 353.65 million Btu (33.48%). Annual utility bill has increased by $1,483.00 which is 1.88% higher than the base case. 15.7 tonnes of greenhouse gas can be reduced if the proposed case is adopted.

Analysis of the Water Intake Technology of Open-Lakes Water Source Heat Pump System in Chongqing

2011 ◽  
Vol 250-253 ◽  
pp. 3168-3172
Author(s):  
Gong Duan Fan ◽  
Zhi Zhang ◽  
Jing Luo ◽  
Xin Wan ◽  
Chao Liu
Keyword(s):  
Water Quality ◽  
Water Temperature ◽  
Heat Pump ◽  
Water Intake ◽  
Lower Layer ◽  
Water Source ◽  
Pump System ◽  
Heat Pump System ◽  
Distribution Features ◽  
Lakes And Reservoirs

To research the suitable water intake technology of open-lakes Water Source Heat Pump system (WSHPs) in Chongqing, water temperature, water quality and other water features of lake and reservoir are analyzed. Results show that the temperature of water source in Chongqing’s lakes and reservoirs excelled the air temperature, and the water quality basically meets the requirements of open-lakes WSHPs. Thus the water source in Chongqing’s lakes and reservoirs is a hot and cold source of good quality. For depth of water is greater than 6m, there is an obvious vertical stratification of water temperature in summer, which is not obvious in winter. pH value, turbidity and algal density also have obvious characteristics in vertical distribution, while hardness and salinity have little characteristics. According to the spatial and temporal distribution features of water temperature and water quality, water intake head should be installed in the middle and lower layer of the lake. Less investment and water head loss, lower operation and maintenance costs, and higher reliability should be considered when we choose the way of water intake for WSHPs in Chongqing. Water intake ways such as pump truck water intake, pontoon intake, gravity pipe intake, integrated device are alternative. Comparison between technical and economic should be made first.

Refrigerant Subcooling Correlations for Different Expansion Devices for a Non-Intrusive Charge Indicator

2006 ◽  
Author(s):  
Z. Gao ◽  
V. C. Mei
Keyword(s):  
Heat Pump ◽  
Low Cost ◽  
Heat Pumps ◽  
Air Conditioner ◽  
Cooling Mode ◽  
Pump System ◽  
Air Conditioners ◽  
Heat Pump System ◽  
Heating And Cooling ◽  
Expansion Valve

The most common problems affecting residential and light commercial heating, ventilation, and air-conditioning (HVAC) systems are slow refrigerant leaks. Equipment users are usually not aware of the problem until most of the refrigerant has escaped. A low-cost, non-intrusive refrigerant charge indicator has been developed, based on temperature measurements and correlations formed to interpret the measured temperatures. It can be used to provide real time warnings to the equipment users before the majority of refrigerant is escaped. It could be inexpensive and easy to incorporate into existing heat pumps and air conditioners. Extensive laboratory experimental work was performed on a 2-ton window air conditioner and on a 2.5 ton split heat pump system. It was found that the heat pump was not sensitive to slow refrigerant leak because of the long liquid line. Liquid subcooling was measured to determine the system charge status before a substantial amount of refrigerant was leaked. This study reports the finding of correlations formed for liquid subcooling for the orifice plate and thermal expansion valve used on the heat pump system for both heating and cooling mode operation.

Optimal Supply Water Temperature Control of Water Source Heat Pump

Solar Energy ◽  
2005 ◽  
Author(s):  
M. Palahanska-Mavrov ◽  
G. Wang ◽  
M. Liu
Keyword(s):  
Potential Energy ◽  
Water Temperature ◽  
Heat Pump ◽  
Temperature Control ◽  
Energy Cost ◽  
Energy Savings ◽  
Water Source ◽  
Theoretical Models ◽  
The Impact ◽  
Supply Water

The water loop supply water temperature is the most critical control parameter for operating energy cost in water source heat pump systems. In this paper, the impact of the water loop temperature on operating energy cost is investigated for different types of buildings under different loads using theoretical models. The theoretical models and approaches are also applied to an 80,000 square feet office building to determine the building heating and cooling load, optimal supply water temperature, and potential energy cost savings based on measured supply water temperature and loop heat gain. It is concluded that the optimal supply water temperature control can significantly reduce the annual energy costs associated with compressor power and boiler energy. The potential energy savings is determined to be 24% in the application building.

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