[ Home ] [ Encapsulation ] [ Mathematical Modelling ] [ PCM Solar Energy Storage ] [ PCM Energy Storage ] [ PCM's In Building Materials ] [ PCM's ]

Chahroudi, D. (1976). Thermocrete heat storage materials: applications and performance specifications. Sharing The Sun Solar Technology In The Seventies A Joint Conference Of The American Section Of The International Solar Energy Society and The Solar Energy Society Of Canada Inc, Winnipeg, The American Section Of The International Solar Energy Society.

Thermocrete energy storage materials are made by combining phase change materials with open cell cements to produce low cost energy storage materials with structural and thermostatic properties. Thermocrete blocks, tiles and panels can be manufactured and installed as either isolated modular units coupled to conventional HVAC or solar collector systems or used to provide distributed heat storage throughout the building fabric when integrated with standard structural components or interior and exterior building finishes. Potential application areas for Thermocrete materials are discussed in general terms. Thermocrete blocks are specifically analysed in more detail concerning modes of operation, performance specifications and energy savings in various applications.

Chahroudi, D. (1978). Development Of Thermocrete Heat Storage Materials. Proceedings Of The International Solar Energy Congress, New Delhi, India.

Thermocrete is a heat storage media combining an appropriate phase change material with a concrete matrix resulting in isothermal storage. structural load bearing capability and good volumetric efficiency. Program goals and development progress is summarised, including performance and cost data. Future work is described.

Chandra, S., S. Kumar, et al. (1985). "Thermal performance of a non-air-conditioned building with PCM thermal storage wall." Energy conversion management 25: 15-20.

This paper presents a time-dependant periodic heat transfer analysis of a non-air-conditioned building having a south-facing wall of phase-change component material (PCCM). A rectangular room (6´ 5´ 4m) based on the ground is considered. The effects of heat transfer through walls and roof, heat conduction to the basement ground and furnishings, heat gain through window and heat loss due to air ventilation have been incorporated in the periodic time-dependent heat transfer analysis. The time-dependent heat flux through the PCCM south-facing wall has been obtained by defining the effective thermal properties of the PCCM for a conduction process with no phase change. Numerical calculations are made for a typical mild winter day (7 March 1979) at New Delhi for heat flux entering through the wall and inside temperature. Further a PCCM wall of smaller thickness is more desirable, in comparison to an ordinary masonry concrete wall, for providing efficient thermal energy storage as well as excellent thermal comfort in buildings.

Collier, R. K. and D. P. Grimmer (1979). The experimental evaluation of phase change material building walls using small passive test boxes. 3rd national Passive Solar Conference

Feldman, D., D. Banu, et al. (1991). "Obtaining An Energy Storing Building material By Direct Incorporation Of An Organic Phase Change Material In Gypsum Wallboard." Solar Energy Materials 22: 231-242.

A laboratory scale energy storage gypsum wall board was produced by the direct incorporation of 21%-22% commercial grade butyl stearate (BS) at the mixing stage of conventional gypsum board production. The incorporation of BS was strongly facilitated by the presence and type of small amounts of dispersing agents. The physio-mechanical properties of the laboratory produced thermal storage wallboard compare quite well with values obtained for standard gypsum board. the energy storing board has a ten fold increase in capacity for the storage and discharge of heat when compared with gypsum wallboard alone

Feustel, H. E. (1995). Simplified numerical description of latent storage characteristics for phase change wallboard. Indoor environmental program energy and environment division Lawrence Berkely Laboratory University of California.

Cooling of residential California buildings contributes significantly to electrical consumption and peak power demand. Thermal mass can be utilised to reduce the peak-power demand, down-size the cooling systems and/or switch to low energy cooling sources.

Large thermal storage devices have been used in the past to overcome the short-comings of alternative cooling sources or to avoid high demand charges. With the advent of phase change material (PCM) implemented in gypsum board, plaster or other wall covering material, thermal storage can be part of the building structure even for light-weight buildings. PCMs have two important advantages as storage media: they can offer an order-of-magnitude increase in thermal storage capacity and their discharge is almost isothermal. This allows to store large amounts of energy without significantly changing the temperature of the sheathing. As heat storage takes place in the building part where the loads occur, rather than externally (e.g. ice or chilled water storage), additional transport energy is not needed.

To numerically evaluate the latent storage performance of treated wallboard, RADCOOL, a thermal building simulation model based on the finite difference approach, will be used. RADCOOL has been developed in the SPARK environment in order to be compatible with the new family of simulation tools being developed at Lawrence Berkely Laboratory. As logical statements are difficult to use in SPARK, a continuous function for the specific heat and the enthalpy had to be found. This report covers the development of a simplified description of latent storage characteristics for wallboard treated with phase change material

Hawes, D. W., D. Feldman, et al. (1993). "Latent heat storage in building materials." Energy and Buildings 20: 77-86.

Thermal storage is an important aspect of energy conservation, which is greatly assisted by the incorporation of latent heat storage in building products. This can be achieved by the use of various phase change materials (PCMs), which absorb and release heat much more effectively than conventional building materials. Different types of PCMs and their characteristics are described. The performance of gypsum wallboard and concrete block, which have been impregnated with PCMs are examined. Manufacturing techniques are considered and applications of PCM wallboard and PCM concrete blocks are discussed.

Kedl, R. J. and S. T.K (1989). Activities in support of the wax-impregnated wallboard concept. U.S Department of energy thermal energy storage research activities review. New Orleans. Lousiana, U.S department of Energy.

The concept of octadene wax impregnated wallboard for the passive solar application, is a major thrust of the Oak Ridge national Laboratory (ORNL) Thermal Energy Storage (TES) program. Thus, ORNL has initiated a number of internal efforts in support of this concept. The results of these efforts are:

1. The immersion process for filling wallboard with wax has been successfully scaled up from small samples to full-size sheets.

2. Analysis shows that the immersion process has the potential for achieving higher storage capacity than adding wax-filled pellets to wallboard during its manufacture.

3. Analysis indicates that 75° F is close to an optimum phase change temperature for the non-passive solar application.

4. The thermal conductivity of wallboard without wax has been measured and will be measured for wax impregnated wallboard. In addition, efforts are underway to confirm an analytical model that handles phase change wallboard for the passive solar application.

Levik, O. I. (1998). Hydrates [online]. Available from: http://www.ipt.unit.no/~levik/hydrates.html [accessed 3 Mar 2000]

Neeper, D. A. (1989). "Potential benefits of distributed PCM Thermal." American Solar Energy Society.

This report examines the benefits of passive thermal storage by means of phase change material (PCM) distributed throughout the wall and ceiling surfaces of a building, as would occur if the wallboard were impregnated with PCM. Surface heat transfer is expected to be adequate for thermal storage capacity up to 40-Btu.ft2 of surface area. Sums of daily energy balances during the heating season indicate that use of PCM-impregnated wallboard with a 40-Btu/ft2 capacity would provide adequate storage for direct gain systems with the largest practical window area in Denver, Boston, and Fort Worth. It is shown that distributed PCM thermal storage offers the opportunity to obtain several ton hours of ventilation cooling per night throughout much of the U.S during July.

Stetiu, C. and H. E. Feustel. Phase-change wallboard and mechanical night ventilation in commercial buildings [online]. Available from: http://oxford.elsevier.com [accessed 25 Feb 2000].

As thermal storage media. PCM's such as paraffin, eutectic salts, etc offer an order of magnitude increase in thermal storage capacity, and their discharge is almost isothermal. Bt bedding PCM's in gypsum board, plaster, or other wall-covering materials, the building structure acquires latent storage properties. structural elements containing PCM's can store large amounts of energy while maintaining the indoor temperature within a relatively narrow range. As heat storage takes place inside the building where the loads occur, rather than at a central exterior location, the internal loads are removed without the need for additional transport energy. Distributed latent storage can thus be used to reduce the peak power demand of a building, downsize the cooling system, and/or switch to low-energy cooling sources.

We used RADCOOL. a thermal building simulation program based on the finite difference approach, to numerically evaluate the thermal performance of PCM wallboard in an office building environment. We found that the use of PCM wallboard coupled with mechanical night ventilation on office buildings offers the opportunity for system downsizing in climates where the outside air temperature drops below 18oC at night. In climates where the outside air temperature remains above 18oC at night, the use of PCM wallboard should be coupled with discharge mechanisms other than mechanical night ventilation with outside air.

Stetiu, C. and H. E. Feustel (1996). Phase change wallboard as an alternative to compressor cooling in Californian residences. In proceedings: 96 ACEE summer study for energy efficient buildings. A Silomar, California.

Large thermal storage devices have been used in the past to overcome the shortcomings of alternative cooling sources, or to avoid high demand charges. The manufacturing of phase change material (PCM) implemented in gypsum board, plaster or other wall-covering material, would the thermal storage to become part of the building structure. PCMs have two important advantages as storage media: they can offer an order-of-magnitude increase in thermal storage capacity, and their discharge is almost isothermal. This allows the storage of high amounts of energy without significantly changing the temperature of the room envelope. As heat storage takes place inside the building, where the loads occur, rather than externally. additional transport energy is not required.

RADCOOL, a thermal building simulation program based on the finite difference approach, was used to numerically evaluate the latent storage performance of treated wallboard. RADCOOL was developed in the SPARK environment in order to achieve compatibility with the new family of simulation tools under development at the Lawrence Berkeley National Laboratory.

Simulation results for a living room with high internal loads and weather data for Sunnyvale, California, show significant reduction of room air temperature when conventional wallboards are replaced with PCM-treated wallboards. Extended storage capacity obtained by using double wallboard is able to keep the room air temperatures within the comfort limits without using any mechanical cooling.

Stoval, T. K. and J. J. Tomlinson (1992). What are the potential benefits of including latent storage in common wallboard, Oak Ridge National Laboratory.

Previous work has shown that wallboard can be successfully manufactured to contain up to 30 percent phase change material (PCM) or wax, thus enabling this common building material to serve as a thermal energy storage device. This material was analysed for passive solar applications and found to save energy with a reasonable pay-back time periods. Further evaluations of the wallboard are reported in this paper. This analysis looks at potential applications of PCM wallboard as a load management device and as a comfort enhancer. Results show that the wallboard is ineffective in modifying the comfort level but can provide significant load management relief with no energy penalty. Modifications to typical heating and air-conditioner control strategies were necessary for successful load management.

Stoval, T. K. and J. J. Tomlinson (1992). What are the potential benefits of including latent storage in common wallboard, Oak Ridge National Laboratory.

Previous work has shown that wallboard can be successfully manufactured to contain up to 30 percent phase change material (PCM) or wax, thus enabling this common building material to serve as a thermal energy storage device. This material was analysed for passive solar applications and found to save energy with a reasonable pay-back time periods. Further evaluations of the wallboard are reported in this paper. This analysis looks at potential applications of PCM wallboard as a load management device and as a comfort enhancer. Results show that the wallboard is ineffective in modifying the comfort level but can provide significant load management relief with no energy penalty. Modifications to typical heating and air-conditioner control strategies were necessary for successful load management.

U.S Department of Energy. (2000). Phase Change Drywall [online]. Available from: http://www.eren.doe.gov/consumerinfo.refbiefs/db3.html [accessed 25 Feb 2000].

U.S. Department of Energy. Phase Change Materials For Solar Heat Storage [online]. Available from: http://www.eren.doe.gov/consumerinfo/refbriefs/b103.html [accessed on 25 Feb 2000].