Seawater Source Heat Pump System Research Articles

Experimental Investigation of the Heat Transfer Characteristics of a Helical Coil Heat Exchanger for a Seawater-Source Heat Pump

AbstractIn this study, a high-density polyethylene helical coil heat exchanger (HCHE) is firstly adopted by a seawater-source heat pump system (SWHP) and experiments are conducted to determine the ...

The thermal performance of seawater-source heat pump systems in areas of severe cold during winter

The research concerning ocean energy exploitation in North China is undoubtedly of significant importance to the development of the national ocean energy. The use of seawater heat pump (SWHP) systems is a better choice than air-source heat pump (ASHP) systems. The latter systems have a lower efficiency because of the formation of frost on the surface of its airside heat exchanger when the ambient air temperature is low. This paper reports research investigating the system efficiency of SWHP systems in areas of severe cold during winter. Experiments are conducted to compare the thermal performance of the beach well infiltration intake systems (BWIS) and the helical coil heat exchanger (HCHE) for SWHP systems in the Bohai Sea, Tianjin, North China. Heat transfer rate, COP (coefficient of performance) values, exergy efficiencies and exergy destruction rates of the SWHP systems with BWIS and HCHE are presented and compared with the ASHP systems. The study results indicate that the BWIS for SWHP systems has the highest thermal performance during the whole heating season in areas of severe cold during winter. That performance is observed because icing on the outer surfaces of the tubes of the HCHE and frost formation on the surface of the heat exchanger of the ASHP have great effects on the heat transfer performance. The Heating seasonal performance factor (HSPF) is used to express the performance of heat pump systems over the entire heating season. Economic analyses of the BWIS and HCHE are performed according to local economics to compare the application of the HCHE and BWIS, and the results indicate that the HCHE has a better economic value.

Potential to enhance performance of seawater-source heat pump by series operation

In this study, the performance enhancement potential by series operation in seawater-source heat pump system, assumed installed in Gangneung city near the East Sea in Korea, was investigated. An annual heating load for a typical Korean-style apartment house, which has an effective area of about 85 m2, was modeled by using TRNSYS program. An ambient condition was assumed to be in accordance with the Korean standard meteorological data, while the seawater temperature was calculated from the regression equation based on the measurement. A heat pump performance at full-load was calculated from the regression equation, which involves refrigerant's evaporating and condensing temperatures, based on a commercial screw compressor performance map. A part-load performance was also considered. Simulation results show that an annual heating performance of a seawater-source heat pump system can be improved by 8% or more by series operation under the simulation conditions considered in the present study.

Heat transfer analysis and experimental verification of cast heat exchanger

From the viewpoints of environmental conservation and energy efficiency, seawater-source heat pump system (SWHP) to provide district cooling and heating is applied in coastal areas. Based on the system, a heat transfer model was established for cast heat exchanger (CHE) adopted by SWHP systems. The CHE consists of pipes immersed in the seawater and used for transferring heat between the seawater and the heat exchanger pipes of SWHP system. An experimental study was carried out to test the validity of the model. A program was developed in VB language and the effects of inlet temperature, flow rate of the secondary refrigerant and length of CHE on the results were investigated. The results of the numerical simulation are in consistence with the experiments in both winter and summer conditions. As a result, application of SWHP systems with CHE in coastal areas in China is feasible due to the favorable geographical conditions and environment.

Heat transfer analysis and experimental verification of casted heat exchanger in non-icing and icing conditions in winter

Seawater-source heat pump systems (SWHP) are recognized to be outstanding heating, cooling and water heating systems. A large number of SWHP systems have been used in residential and commercial buildings in coastal areas due to the attractive advantages of high efficiency and environmental friendliness. In this paper, two mathematical models that described heat transfer process of casted heat exchanger (CHE) adopted by SWHP systems in the icing and non-icing conditions in winter have been developed and validated by an experimental study. The CHE is consisted of pipes immersed in the seawater and used for transferring heat between the seawater and the heat exchanger pipes of the SWHP. In addition, a computer code has been implemented to simulate the effects of flow rate of the secondary refrigerant, length of the CHE and the temperature of the seawater on the heat transfer performance. The effect of the ice outside the pipe due to the low seawater temperature on heat transfer has been discussed and the comparison of the heat transfer rate in two conditions demonstrates that the effect of icing on heat transfer performance is great. As a result, application of SWHP systems with CHE in coastal areas in China is feasible due to the favorable geographical conditions and environment.

Thermoeconomic Optimization of a Seawater Source Heat Pump System for Residential Buildings

A seawater source heat pump (SWHP) system offer an attractive option for heating and cooling residential and commercial buildings owing to their higher energy efficiency compared with conventional systems. A thermoeconomic model was developed for analysis and optimization of SWHP with residential building. The thermodynamic and thermoeconomic optimum result for SWHP in the Qingdao, china, weather conditions were obtained using MATLAB optimization toolbox. The thermoeconomic optimization results show exergy loss and EER increasing by 22.7% and 13.9% respectively, but annual production costs reduce by 29.1%.

Modeling and Exergy Analysis of Seawater Source Heat Pump System

A seawater source heat pump (SWHP) system refers to the utilization of solar energy stored in sea water as heat source and heat sink , offer an attractive option for heating and cooling residential and commercial buildings owing to their higher energy efficiency compared with conventional systems The purpose of this study is to present an exergy analysis of a SWHP system The exergy transports between the components and the consumptions in each of the components of the SWHP system were determined for the average measured parameters obtained from the experimental results. In addition the exergy loss was presented for the SWHP system studied to give quantitative information regarding the proportion of the exergy input that is dissipated in the various system components.

Applications of Seawater Source Heat Pump in Buildings

In the area of using renewable energy, promoting the efficiency of seawater source heat pump plays an important part. Several nontraditional technologies are can be used in the new seawater source heat pump system. As for the intake system, infiltration intake technology is introduced, which can increase the supply temperature of sea water and thus raise the efficiency of the system. And as for the terminals, a new-style PVC low temperature water flowing radiant heating (LTWFRH) system is used to match the temperature characteristics of seawater source. After the optimization of the whole system, the seawater source heat pump can be more efficiency and thus saving more energy, considering the energy conservation effect of seawater source heat pump itself.

Modeling and Experimental Verification of Casted Heat Exchanger in Non-Icing and Icing Conditions in Winter

A large number of seawater-source heat pump systems (SWHP) have been used in residential and commercial buildings in coastal areas due to the attractive advantages of high efficiency and environmental friendliness. To overcome the disadvantages of the open loop SWHP in winter of cold regions, a closed loop SWHP system with casted heat exchanger (CHE) is presented in this paper. The CHE is consisted of pipes immersed in the seawater and used for transferring heat between the seawater and the heat exchanger pipes of the SWHP. In addition, two mathematical models that described heat transfer process of CHE in the icing and non-icing conditions in winter have been developed and validated by an experimental study. The temperature distributions along the CHE were compared between the experimental data and numerical simulation results. The relative error is less than 5%. As a result, application of SWHP systems with CHE in coastal areas in China is feasible due to the favorable geographical conditions and environment.

Study on the decision-making of district cooling and heating systems by means of value engineering

A district cooling and heating (DCH) system can provide both cooling and heating for blocks of buildings in cold climate areas, however, different thermal source schemes of a DCH project always differ in their first cost, operating cost, maintenance cost, regulation performance, control performance, energy-saving and environment protection performance, etc. In order to evaluate various DCH thermal source schemes quantitatively, the paper firstly establishes an evaluation model based on value engineering theory. It then elaborates on how this model is applied in the first seawater source heat pump DCH project in China—Dalian Xinghai Bay project. The calculation results show that even though the scheme of seawater source heat pump system is not economical under commercial electricity price mainly because of its relatively high initial cost, yet it has the highest value coefficient under civil electricity price. This also implies that privileges of policy for renewable energy utilization system are necessary to help promote the energy-saving and environment-friendly scheme of seawater source heat pump system.

Application of seawater source heat pump

A seawater source heat pump (SWHP) system refers to a heat pump system which harnesses the ocean's thermal energy as a means of generating renewable energy. The design and application of a SWHP system is discussed, including operational feasibility, system features, system principles and the design method. In addition, based on about one year's worth of operational data, a case study is developed for the system under automatic and variable flowrate operation. Results indicate that a SWHP provides a generally steady and continuous source of heating and cooling, with seawater acting as a stable and reliable heat source and heat sink. In transitional seasons, when a much lower flow is required to satisfy the heating and cooling load of the building space, such a system saves energy because of a system performance factor (PF) of ∼3·83, which is 1·24 times higher than that at the maximum flowrate. This study indicates that it is technically and economically feasible to apply a SWHP system in coastal cities such as Qingdao.