Page 1 of 19

European Journal of Applied Sciences – Vol. 12, No. 4

Publication Date: August 25, 2024

DOI:10.14738/aivp.124.17265.

Ekoe, A. A. M., Mackpayen, A. O., Kennedy, N. O., & Robert, M. (2024). Phase Change Material for Thermal Comfort

Improvement in Tropical Climate of Cameroon. European Journal of Applied Sciences, Vol - 12(4). 50-68.

Services for Science and Education – United Kingdom

Phase Change Material for Thermal Comfort Improvement in

Tropical Climate of Cameroon

Aloys Martial Ekoe A Akata

Renewable Energy Systems Technology Laboratory (RESTL),

Department of Physics, Faculty of Science, University of Douala, Cameroon

Corresponding author: ekoealoys@yahoo.fr, Tel: +237 67631 7345

Auguste Oscar Mackpayen

Laboratoire d’Energétique Carnot (L.E.C) /

Université de Bangui, B.P: 908 Bangui (RCA)

Nembot Ouembe Kennedy

Renewable Energy Systems Technology Laboratory (RESTL),

Department of Physics, Faculty of Science, University of Douala, Cameroon

Mbiake Robert

Renewable Energy Systems Technology Laboratory (RESTL),

Department of Physics, Faculty of Science, University of Douala, Cameroon

ABSTRACT

Current typical dwellings in the Sub-Saharan tropical climate of Cameroon provide

opportunities for more effective design and the use of Phase-change materials

(PCM) to reduce cooling energy demand. In this paper, a typical residential house

of a single family is modelled with the local construction habits and materials

under the tropical region of Cameroon. Energy analysis of the building is

performed, taking into account the use of PCM paraffin RT26 in order to enhance

the thermal comfort of the building. The impact of using phase change material on

indoor air temperature is quantified. The results of the numerical analysis

obtained show that the PCM can be a good option in a hot climate for reducing

indoor air temperature. The average annual indoor air temperature was reduced

from 35°C to 25°C.

Keywords: Numerical simulation, Phase change material, Indoor air temperature,

Thermal comfort.

INTRODUCTION

Whatever the building to build or manage, solutions to control energy demand must be

sought. This is true in the world for all types of buildings, industrial, commercial or

residential, and especially in developing countries where the building sector, which covers

commercial and public buildings, includes many types of buildings (schools, restaurants,

hotels, hospitals, museums, etc.) with a wide variety of energy using services (HVAC, hot

water, lighting, refrigeration, food preparation, etc.) accounts for a 50 – 60 % of national

energy consumption [1]. Before designing or improving a building, it is essential to study its

Page 2 of 19

51

Ekoe, A. A. M., Mackpayen, A. O., Kennedy, N. O., & Robert, M. (2024). Phase Change Material for Thermal Comfort Improvement in Tropical

Climate of Cameroon. European Journal of Applied Sciences, Vol - 12(4). 50-68.

URL: http://dx.doi.org/10.14738/aivp.124.17265

energy needs and energy sources available, look for the most adequat management system,

distribution network and consumer equipment taking into account operating requirements.

Many buildings in Africans developing countries were constructed without any energy

performance study due to the lack of local building energy codes and standards for low

energy demand. The result of these actions was a very high energy consumption from the

residential sector. Around 63 % of the Sub-Saharan African (SSA) population lives in rural

areas, one of the highest shares of any world region, which has important implications for the

approach to solve the energy challenges. Access to minimum electricity in the region are

crucial for economic and social development. The available data shows that the electricity

consumption in SSA is currently approx. 550 kWh/year average per capita (compared to 920

kWh in India and 2’300 kWh in Asia), is growing quickly and a large portion remains latent

due to the low access levels [2].

Reducing building energy demand in new building construction or renovation to obtain a Net

Zero Energy Building (NZEB) can be accomplished through various means, including

integrated design, energy efficiency retrofits, reduced plug loads and energy conservation

programs incorporated using architectural and building envelope design, orientation of the

construction, façade design, self-shading, ventilation, lighting and daylighting, renewable

energy systems, phase change materials and more.

The Orientation of the building is the direction of a building in relation to the variations of the

sun’s path. The building orientation has a significant impact on the overall thermal

performance when significant differences between individual facades especially in regard to

window sizes are present. Abanda et al. [3] investigated the impact of building orientation on

energy demand in a domestic building using emerging building information modelling. They

found that an appropriate building orientation can save a considerable amount of energy

throughout its life cycle. The Orientation of a building in hot climates should aim to exclude as

much as possible direct sunlight, hot winds and nearby radiant heat from other structures

while ensuring access to cooling breezes.

The building envelope which includes the roof, walls, windows, glazing, and floors is decisive

for an energy efficient building. Developing a high-performance building envelope is an

important part of designing zero energy buildings. The requirements for high performance

envelopes should be considered in regard to the thermal performance, acoustics, ventilation,

renewable energy harvest, visual aesthetics, air quality, fire resistance and the solidity of the

building structure. Therefore, the building envelope presents great opportunities for

improvements. The particular attention in Sub-Saharan climate should be on the

improvement of the local materials used for the construction of external walls due to the lack

of efficient insulation materials. Roof construction and false ceilings.

In the Cameroonian context, a false ceiling is a solid and horizontal surface that closes up the

indoor space parallel to the floor. It is made up of local materials, especially wood. The false

ceiling is used for decoration of the indoor space and the hiding of electric cables. It can also

be used for the installation of ceiling fans and light fixtures. The space between the false

ceiling and the roof top is referred to as the dead space in this study. the roof top are mainly

Page 3 of 19

Services for Science and Education – United Kingdom 52

European Journal of Applied Sciences (EJAS) Vol. 12, Issue 4, August-2024

made up of Aluminum due to its reflecting properties. The Aluminum sheets are fixed with

wooden slats, to prevent them to be carried away by wind. This construction style is

reproduced in almost all the buildings in urban areas.

In this paper, a typical single-family residential house is modelled with local constructions

and materials and simulated under the tropical climate of Cameroon. Energy analysis of the

building is performed taking into account building parameters such as the design of the

construction, the orientation of the building, the envelope structure and it’s materials, the use

of phase change materials (PCM) in order to improve the building air temperature.

PHASE CHANGE MATERIALS

A material that changes its phase, i.e. melts/evaporates and solidifies/condensates in a

temperature range which is of interest in the building sector can be used to increase the

thermal inertia of constructions and is referred to as a phase change material (PCM). PCMs

are divided into 4 main groups, depending on their chemical characteristics. There are:

1- Water-based ice and gel packs (low-cost, nontoxic, non-flammable, easy to use but

only useful for 0 °C applications);

2- Salt hydrates (melting points: 15 °C to 80 °C. Low material costs, high latent heat

storage capacity, high thermal conductivity, inflammability but vulnerable to

supercooling, volume change of up to 10 % in solid/liquid phase change, latent heat

capacity lost and recrystallization following each cycle, toxic and many are corrosive to

metals);

3- Paraffins (melting points 8 °C to 40 °C. Good thermal storage capacity, freeze without

subcooling, chemical stability, non-corrosive, compatible with most encapsulation

materials but their cost is linked to unstable petroleum prices, health problems, some

can injure skin, eyes and mucous membranes, narcotic effects if inhaled)

4- Biobased PCMs (organic compounds derived from animal fat and plant oils with the

melting point temperatures ranging between -40 °C and 150 °C. They are nontoxic,

minimal volume change between phases, stable, have high latent heat, fire-resistant,

cheaper than petroleum-based PCMs) [4].

PCMs undoubtedly have a certain potential to reduce air conditioning demands while

maintaining a good level of thermal comfort in buildings with otherwise low inertia. However,

several areas of improvement are still the subject of specific research such as: the definition of

the best melting / solidification range, fire behaviour, characterization of any emitted

secondary products (potential harm), conditioning and durability in the melting/solidification

cycles, the possibility of coupling phase change materials and vacuum insulation panels (VIP)

to achieve lightweight envelopes with both good insulation and significant thermal inertia,

however combined with excruciatingly high costs. The choice of PCM is typically made based

on the material properties such as the melting/solidification temperatures, density, thermal

conductivity, latent heat, sharpness of latent heat release and absorption, stability to cycling

and ageing, non-corrosiveness to encapsulation, cost effectiveness and safety in use. The

working temperature range will define the final applicability of a given PCM. Cabeza et al.

[5,6] compiled information about PCM technology and the classification of materials, the

availability, the cost and their application in buildings.