Elsevier

Energy and Buildings

Volume 67, December 2013, Pages 56-69
Energy and Buildings

Review of thermal energy storage technologies based on PCM application in buildings

https://doi.org/10.1016/j.enbuild.2013.08.006Get rights and content

Highlights

Abstract

Thermal energy storage systems (TES), using phase change material (PCM) in buildings, are widely investigated technologies and a fast developing research area. Therefore, there is a need for regular and consistent reviews of the published studies. This review is focused on PCM technologies developed to serve the building industry. Various PCM technologies tailored for building applications are studied with respect to technological potential to improve indoor environment, increase thermal inertia and decrease energy use for building operation. What is more, in this review special attention is paid to discussion and identification of proper methods to correctly determine the thermal properties of PCM materials and their composites and as well procedures to determine their energy storage and saving potential. The purpose of the paper is to highlight promising technologies for PCM application in buildings with focus on room application and to indicate in which applications the potential is less significant.

Introduction

In general, heat storage is a very interesting technique to decrease energy use in the buildings and to reduce the cost of operation of buildings. Therefore, during recent decades a variety of heat storage solutions for the building market have been developed. Some of the advantages of heat storage in the buildings are as follows: reduction of peak power for heating and cooling, possibility to shift peak heating and cooling loads to the low tariff hours, shifting temperature peaks to non-working hours, improvement of indoor environment, and efficient utilization of passive heating and cooling loads.

Thermal energy storage (TES) can be divided into sensible heat storage and latent heat storage systems. It is worth mentioning that each latent heat storage system also always represents sensible heat storage, but this one is usually very small compared to the latent heat capacity, and therefore the latent heat storage is more interesting and has drawn much attention during the last decades. For example, ordinary building materials such as concrete and gypsum only represent the sensible heat storage capacity, which varies approximately between 0.75 and 1 kJ/(kg K) whereas, for example, some average paraffin materials, which undergo phase change have latent heat storage capacity of approximately 110 kJ/kg. This means that due to very high heat storage potential, a much smaller volume of the material is needed to store the same amount of energy. The other advantage of phase change materials (PCM) is that within the phase change their temperature remains almost constant. Thanks to this characteristic, the temperature stratification in the spaces has been reported to be minimized, and too high temperatures of the surfaces of constructions prevented. However, despite of all the mentioned advantages and very large number of research projects on PCMs, the most of PCM products do not find commercial implementation and the ones that do are still in the niche. Even though some of the products are implemented in the buildings, there are no real case studies on the performance of PCM in buildings, and the only information available is limited to the small prototype laboratory tests. Moreover, although the thermal properties of many PCMs are well analyzed and documented, the whole picture of the conditions required to activate thermal mass are often omitted or unrealistic experimental scenarios are studied. As a result of that, either incomplete conclusion are drawn or overestimated performance is indicated. Furthermore, an economic analysis of the application of PCMs is never documented, and even simple information about cost of such materials is not easy to obtain by someone potentially interested.

The purpose of this paper is to illustrate and sum up the research activities focused on PCM application in the buildings. The center of the focus is the room and PCM applications in the room. Additionally, the paper elaborates on the heat transfer within the room enclosures as this aspect is very often the key parameter that decides to which extent and how efficiently thermal mass of the building is activated.

During recent years, many studies of PCMs and latent heat storage techniques have been reported. Moreover, research topics that can be found in the literature cover various areas of phase change application and features, and as a result it is sometimes difficult to have a clear overview of up to date information, since some of the newer results can be contradicted with regards to some earlier findings. For example, some of the studies are focused on developing new PCMs [1], [2], [3], whereas other categorize and sort out existing candidates with regards to, for example, their thermal and physical properties and melting ranges [4], [5], [6]. Other papers only deal with specific application and potential of technologies using PCMs, and this is a very large group of publications. There are also publications focusing on measuring procedures and techniques to determine the thermal properties of PCMs. These methodologies are not as straight forward as for example for ordinary materials representing only sensible heat [8], [9]. Finally, some of the studies try to improve existing PCMs or latent heat storage solutions by modifying the thermal properties, geometry, or whole system configurations [10], [11], [12]. On top of that, some of the works combine different issues listed above in the text together in one holistic approach to solve the specific research problem. In this huge variety of subjects grouped around the latent heat storage issue, it is often a challenge to find a clear understanding of available studies focused on PCM applications tailored for the building market and – what is also very important – which of them might illustrate solutions that are more promising than others. Another very important issue is to be able to recognize proper testing procedures, boundaries and heating loads that should be taken under consideration, in order to obtain the correct performance potential of the investigated technology.

The attempt of this paper is to gather publications treating PCM application developed for the building market. Different major disciplines are recognized, and relevant publications are grouped within each discipline. Moreover, results from different studies are not only summarized, but in many cases comments on possible improvement or missing information are indicated. In addition, scientific documentation on different technologies utilizing PCMs has been reviewed chronologically in some cases, since it was observed that in many consecutive studies, the outcome of the previous publications was the motivation to subsequent research. Furthermore, special care has been taken to not only list the available literature on the specific topics but also to shortly explain the content of research and the key conclusions. What is also worth highlighting is that the aim of this review is not to elaborate on the properties and the potential of different PCM as such, but always on the specific application in the buildings where the focus is on the PCM application in a room. Although no thermal properties of specific PCMs are listed in the paper, special attention is paid to elaborate on accurate methods available to determine the thermal properties of PCMs or theirs composites. The determination of the thermal properties of PCMs and theirs composites can be challenging. However, it is often an initial and unavoidable step to investigate specific PCM applicability and potential. Also, the focus on the realistic heat transfer within the building envelope enclosures is elaborated, as this is the key parameter influencing to what extent the thermal mass of the building is thermally activated. In the review, a special effort has been made to identify the success criteria of PCM application in buildings but also to identify the challenges and reasons why PCM has such a small share in the real building projects. Based on the scientific evidences, it is concluded when and where PCM has potential for successful application and which criteria has to be known and fulfilled. The article finishes with a recommendation for further research and indications of where further efforts should be made, in order to determine if PCM could be a beneficial and competitive technology.

The paper starts with a summary of recent reviews on PCM materials and as well the technologies implementing PCM in building application. The outcome of the summary of reviews is to sort out the most important groups of PCM applications related to building solutions and also to indicate which research areas are of most interest.

Consequently, different applications of PCM grouped into disciplines are discussed, and the most relevant works are presented. The following disciplines related to building application have been recognized: PCM in construction materials (passive), PCM in thermally activated constructions, PCM in glazing and shading devices, and PCM combined with ventilation and air-conditioning. What is more, the following issues closely related to the building design process and PCM thermal properties have been included in the paper: methods to determine thermal properties of PCMs and their composites, heat transfer enhancement in PCMs, and heat transfer in the room. The paper closes with discussion and conclusions.

Section snippets

Summary of reviews

Over the last decades, several reviews on latent heat storage materials and systems have been published. In the following, some of the most significant ones are shortly summarized and put in chronologic order [5], [6], [13], [14], [15], [16], [17].

In [5], over 230 references related to various topics considering PCMs are given. Firstly, an extensive list of materials representing latent heat storage properties is presented. In the review, PCMs are classified into paraffin, fatty acids, salt

PCM in construction materials (passive)

During recent decades, several bulk encapsulated PCMs were developed for the building applications. However, as stated in [6], the surface area of the most encapsulated commercial products was inadequate to deliver heat to the building after PCM was melted. Therefore, the majority of studies have been focused on PCM integration into the construction elements of the building, such as walls, ceilings and floors. These construction elements offer large areas for heat transfer within building

PCM in construction (active)

Thermally activated panels made of combined gypsum and microencapsulated PCM was presented in [39]. The prototypes were developed to handle heat gains of up to 40 W/m2 due to latent heat incorporation. The inserted capillary tubes were used to remove absorbed heat in the panel. The testing results indicated promising results within the realistic temperature variations. It is worth highlighting, that during the development process it was discovered that the thermal conductivity of gypsum drops

PCM in glazing, shadings, blinds (windows, slats, shutter)

While research on PCM integrated in the opaque constructions is very common and numerous publications resulting in various product development have been documented during the last decades, very few studies have been accomplished on PCM in the transparent materials and shading components.

From the energy use and thermal perspective, windows and glazing represent weak link between internal and external condition in buildings. In the cold climates, windows are responsible for significant heat

PCM in HVAC components/heat exchangers

In this chapter, some of the research documented on the performance of ventilation and air conditioning systems will be listed, combined with various latent heat storage concepts that were documented during approximately last decade. In 2000, a paper [49] on novel ventilation cooling system consisting on latent heat storage and heat pipe was published. The theoretical model over-predicted heat transfer rate by about 100%, but predicted heat pipe surface temperature within 2 °C. Authors indicated

Measurements of specific heat capacity

The correct design of the building or storage system with integrated PCMs requires correct knowledge of the thermal properties of the PCMs used. For example, the single data points, the phase change enthalpy at the melting temperature or the heat of fusion do not describe PCM properties with sufficient accuracy to perform dynamic simulations of a room or a whole building containing PCM. The phase change occurs in a temperature range and not at a constant temperature level, and therefore

Heat transfer enhancement in PCM

The most of PCMs suffer from low thermal conductivities, being around 0.2 W/(m K) for paraffin and 0.5 W/(m K) for salt hydrates. Such low thermal conductivities extend charging and discharging periods of TES systems. In buildings, charging and discharging periods are imposed usually by day (charging) and night (discharging) cycles which are closed within 24 h. As a consequence of the low thermal conductivity of PCMs, not all latent heat might be utilized or the PCM material would not be fully

Heat transfer in the room

Considering thermal activation of thermal mass, both the heat transfer within construction, but as well heat transfer on the surface of the construction has to be taken into account. Within construction, heat is transferred by conduction and the thermal properties, that are describing how fast and how much heat is transferred, are included within expression for thermal inertia (TI) of the materials which the construction is made of. Thermal inertia depends on materials density, specific heat

Discussion

A review of TES using PCM with focus on the building application has been carried out. The information gathered is divided with respect to different application of PCM. From the investigation, it can be concluded that PCM application for passive solutions in construction materials has been studied by many researchers. It was documented that the gypsum materials can be combined by up to 45% by weight of PCM when reinforcing the structure with some additives and up to 60% by weight in the wall

Concluding remarks

In this chapter, some of the key issues regarding PCM applications in the building, which should be taken into account when studying performance of PCM application, are listed. The issues listed illustrate key observations and conclusions made during preparation of this review.

  • When studying the potential of PCM products, boundary condition (temperature fluctuation, heat transfer on the surface) and heating loads in experimental set ups and in simulations have to represent realistic condition,

Acknowledgements

This work is collectively sponsored by the Danish Agency for Science, Technology and Innovation and the Ministry of Science and Technology of P.R. China in the Sino-Danish collaborated research project: “Activating the Building Construction for Building Environment Control” (Danish International DSF project No. 09-71598, Chinese international collaboration project No. 2010DFA62410).

References (77)

  • N. Zhu et al.

    Dynamic characteristics and energy performance of buildings using phase change materials: a review

    Energy Conservation and Management

    (2009)
  • M. Delgado et al.

    Review on phase change material emulsions and microencapsulated phase change material slurries: materials, heat transfer studies and applications

    Renewable and Sustainable Energy Reviews

    (2012)
  • E. Osterman et al.

    Review of PCM based cooling technologies for buildings

    Energy and Buildings

    (2012)
  • C. Voelker et al.

    Temperature reduction due to the application of phase change materials

    Energy and Buildings

    (2008)
  • P. Schossig et al.

    Micro-encapsulated phase-change materials integrated into construction materials

    Solar Energy Materials and Solar Cells

    (2005)
  • F. Kuznik et al.

    Experimental assessment of phase change material for wall building use

    Applied Energy

    (2009)
  • F. Kuznik et al.

    Experimental investigation of wallboard containing phase change material: data for validation of numerical modeling

    Energy and Buildings

    (2009)
  • A. Oliver

    Thermal characterization of gypsum boards with PCM included: Thermal energy storage in buildings through latent heat

    Energy and Buildings

    (2012)
  • H. Liu et al.

    Performance of phase change material boards under natural convection

    Building and Environment

    (2009)
  • L. Shilei et al.

    Experimental study and evaluation of latent heat storage in phase change materials wallboards

    Energy and Buildings

    (2007)
  • L. Shilei et al.

    Impact of phase change wall room on indoor thermal environment in winter

    Energy and Buildings

    (2006)
  • A.G. Entrop et al.

    Experimental research on the use of micro-encapsulated Phase Change Materials to store solar energy in concrete floors and to save energy in Dutch houses

    Solar Energy

    (2011)
  • L.F. Cabeza et al.

    Use of microencapsulated PCM in concrete walls for energy savings

    Energy and Buildings

    (2007)
  • P. Arce et al.

    Use of microencapsulated PCM in buildings and the effect of adding awnings

    Energy and Buildings

    (2012)
  • M. Hunger et al.

    The behaviour of self-compacting concrete containing micro-encapsulated phase change materials

    Cement and Concrete Composites

    (2009)
  • M. Pomianowski et al.

    Dynamic heat storage and cooling capacity of a concrete deck with PCM and thermally activated building system

    Energy and Buildings

    (2012)
  • A. Castell et al.

    Experimental study of using PCM in brick constructive solutions for passive cooling

    Energy and Buildings

    (2010)
  • T. Silva et al.

    Experimental testing and numerical modelling of masonry solution with PCM incorporation: a passive construction solution

    Energy and Buildings

    (2012)
  • A. Sari et al.

    Preparation, thermal properties and thermal reliability of palmitic acid/expanded graphite composite as form-stable PCM for thermal energy storage

    Solar Energy Materials and Solar Cells

    (2009)
  • J. Marin et al.

    Improvement of a thermal energy storage using plates with paraffin–graphite composite

    Heat and Mass Transfer

    (2005)
  • I. Cerón et al.

    Experimental tile with phase change materials (PCM) for building use

    Energy and Buildings

    (2011)
  • M. Koschenz et al.

    Development of a thermally activated ceiling panel with PCM for application in lightweight and retrofitted buildings

    Energy and Buildings

    (2004)
  • R. Ansuini et al.

    Radiant floors with PCM for indoor temperature control

    Energy and Buidlings

    (2011)
  • X. Jin et al.

    Thermal analysis of a double layer phase change material floor

    Applied Thermal Engineering

    (2011)
  • K. Lin et al.

    Modeling and simualtion of under-floor electric heating system with shape-stabilized PCM plates

    Building and Environment

    (2004)
  • H. Manz et al.

    TIM-PCM external wall system for solar heating and daylighting

    Solar Energy

    (1997)
  • K.A.R. Ismail et al.

    Parametric study on composite and PCM glass system

    Energy Conversion and Management

    (2002)
  • H. Weinläder et al.

    PCM-facade-panel for daylighting and room heating

    Solar Energy

    (2005)
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