Experimental demonstration of an air-source heat pump application using an integrated phase change material storage as a desuperheater for domestic hot water generation

Integration of a three-media refrigerant/phase change material (PCM)/water heat exchanger (RPW-HEX) in the hot superheated section of a heat pump (HP) system is a promising approach to save energy for domestic hot water (DHW) generation in multi-family houses. The RPW-HEX works as a desuperheater and as a latent thermal energy storage in the system. The latent thermal energy storage is charged during heating and cooling operation and discharged for DHW production. For this purpose, the water side of the RPW-HEX is connected to decentralized DHW storage devices. DHW consumption, building standards and climate, energy prices, material costs, and production costs are the constraints for the selection of the optimal storage size and RPW-HEX design. This contribution presents the techno-economic analysis of the RPW-HEX integrated into an R32 air source HP. With the aid of experimentally validated dynamic computer models, the optimal sizing of the RPW-HEX storage is discussed to maximize energy savings and to minimize the investment costs. The results are discussed in the context of a return of investment analysis, practical implementation aspects and energetic potential of the novel technology.

Download Full-text

Defrosting Performance Improvement of Air-Source Heat Pump Combined Refrigerant Direct-Condensation Radiant Floor Heating System with Phase Change Material

Energies ◽

10.3390/en13184594 ◽

2020 ◽

Vol 13 (18) ◽

pp. 4594 ◽

Cited By ~ 1

Author(s):

Chenxiao Zheng ◽

Shijun You ◽

Huan Zhang ◽

Zeqin Liu ◽

Wandong Zheng ◽

...

Keyword(s):

Phase Change ◽

Phase Change Material ◽

Heat Pump ◽

Heating System ◽

Air Source Heat Pump ◽

Composite Phase Change Material ◽

Radiant Floor Heating System ◽

Radiant Floor Heating ◽

Change Material ◽

Floor Heating

Traditional defrosting methods applied to solve frosting problems of air-source heat pumps operating in cold periods may reduce heat capacity of the system and decrease indoor thermal comfort. In order to improve the performance of air-source heat pump (ASHP) and maintain indoor temperature in defrosting conditions, an air-source heat pump combined with a refrigerant direct-condensation radiant floor heating system with phase change material is proposed and evaluated in this study. Two radiant floor heating terminals with and without composite phase change material modules were compared through experiments. A composite phase change material based on dodecanoic acid-tetradecanol-hexadecanol mixture and expanded graphite was investigated for this application. Experimental results indicate that both heat fluxes of two comparing terminals are higher than 70 W/m2 in heating condition. At the same time, the floor surface temperature, indoor air temperature, and heating capacity of the terminal with composite phase change material modules are higher than those without composite phase change material modules in defrosting condition. This suggests that the proposed system with composite phase change material modules can improve indoor thermal comfort in defrosting condition as well as satisfy the heating requirement in heating condition.

Download Full-text

Effect of using external vertical fins in phase change material modules for domestic hot water tanks.

Renewable Energy and Power Quality Journal ◽

10.24084/repqj04.253 ◽

2006 ◽

Vol 1 (04) ◽

pp. 118-123 ◽

Cited By ~ 2

Author(s):

Albert Castell ◽

Cristian Solé ◽

Marc Medrano ◽

Joan Roca ◽

Daniel García ◽

...

Keyword(s):

Phase Change ◽

Phase Change Material ◽

Hot Water ◽

Domestic Hot Water ◽

Water Tanks ◽

Change Material

Download Full-text

Thermal analysis of including phase change material in a domestic hot water cylinder

Applied Thermal Engineering ◽

10.1016/j.applthermaleng.2011.07.043 ◽

2011 ◽

Vol 31 (17-18) ◽

pp. 3938-3945 ◽

Cited By ~ 60

Author(s):

A. de Gracia ◽

E. Oró ◽

M.M. Farid ◽

L.F. Cabeza

Keyword(s):

Thermal Analysis ◽

Phase Change ◽

Phase Change Material ◽

Hot Water ◽

Domestic Hot Water ◽

Change Material

Download Full-text

Life Cycle Assessment of the Use of Phase Change Material in an Evacuated Solar Tube Collector

Energies ◽

10.3390/en14144146 ◽

2021 ◽

Vol 14 (14) ◽

pp. 4146

Author(s):

Agnieszka Jachura ◽

Robert Sekret

Keyword(s):

Life Cycle Assessment ◽

Life Cycle ◽

Environmental Impact ◽

Phase Change ◽

Phase Change Material ◽

Solar Collector ◽

Hot Water ◽

Production Operation ◽

Management Scenarios ◽

Change Material

This paper presents an environmental impact assessment of the entire cycle of existence of the tube-vacuum solar collector prototype. The innovativeness of the solution involved using a phase change material as a heat-storing material, which was placed inside the collector’s tubes-vacuum. The PCM used in this study was paraffin. The system boundaries contained three phases: production, operation (use phase), and disposal. An ecological life cycle assessment was carried out using the SimaPro software. To compare the environmental impact of heat storage, the amount of heat generated for 15 years, starting from the beginning of a solar installation for preparing domestic hot water for a single-family residential building, was considered the functional unit. Assuming comparable production methods for individual elements of the ETC and waste management scenarios, the reduction in harmful effects on the environment by introducing a PCM that stores heat inside the ETC ranges from 17 to 24%. The performed analyses have also shown that the method itself of manufacturing the materials used for the construction of the solar collector and the choice of the scenario of the disposal of waste during decommissioning the solar collector all play an important role in its environmental assessment. With an increase in the application of the advanced technologies of materials manufacturing and an increase in the amount of waste subjected to recycling, the degree of the solar collector’s environmental impact decreased by 82% compared to its standard manufacture and disposal.

Download Full-text

Comparison of Stratification in a Water Tank and a PCM-Water Tank

ASME 2007 Energy Sustainability Conference ◽

10.1115/es2007-36074 ◽

2007 ◽

Cited By ~ 2

Author(s):

A. Castell ◽

C. Sole´ ◽

M. Medrano ◽

M. Nogue´s ◽

L. F. Cabeza

Keyword(s):

Phase Change ◽

Phase Change Material ◽

Temperature Change ◽

High Energy ◽

Hot Water ◽

The Other ◽

High Energy Density ◽

Water Tank ◽

Charging And Discharging Processes ◽

Change Material

Most of the storage systems available on the market use water as storage medium. Enhancing the storage performance is necessary to increase the performance of most systems. The stratification phenomenon is employed to improve the efficiency of storage tanks. Heat at an intermediate temperature, not high enough to heat up the top layer, can still be used to heat the lower, colder layers. There are a lot of parameters to study the stratification in a water tank such as the Mix Number and the Richardson Number among others. The idea studied here was to use these stratification parameters to compare two tanks with the same dimensions during charging and discharging processes. One of them is a traditional water tank and the other is a PCM-water (a water tank with a Phase Change Material). A PCM is good because it has high energy density if there is a small temperature change, since then the latent heat is much larger than the sensible heat. On the other hand, the temperature change in the top layer of a hot water store with stratification is usually small as it is held as close as possible at or above the temperature for usage. In the system studied the Phase Change Material is placed at the top of the tank, therefore the advantages of the stratification still remain. The aim of this work is to demonstrate that the use of PCM in the upper part of a water tank holds or improves the benefit of the stratification phenomenon.

Download Full-text

Thermal Behavior of Phase Change Material During Charging Inside a Finned Cylindrical Latent Heat Energy Storage System: Effects of the Arrangement and Number of Fins

2010 14th International Heat Transfer Conference, Volume 7 ◽

10.1115/ihtc14-22397 ◽

2010 ◽

Cited By ~ 2

Author(s):

Dominic Groulx ◽

Wilson Ogoh

Keyword(s):

Energy Storage ◽

Phase Change ◽

Phase Change Material ◽

Latent Heat ◽

Storage System ◽

Heat Energy ◽

Hot Water ◽

Heat Of Fusion ◽

Melting Front ◽

Change Material

One way of storing thermal energy is through the use of latent heat energy storage systems. One such system, composed of a cylindrical container filled with paraffin wax, through which a copper pipe carrying hot water is inserted, is presented in this paper. It is shown that the physical processes encountered in the flow of water, the heat transfer by conduction and convection, and the phase change behavior of the phase change material can be modeled numerically using the finite element method. Only charging (melting) is treated in this paper. The appearance and the behavior of the melting front can be simulated by modifying the specific heat of the PCM to account for the increased amount of energy, in the form of latent heat of fusion, needed to melt the PCM over its melting temperature range. The effects of adding fins to the system are also studied, as well as the effects of the water inlet velocity.

Download Full-text