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Investigation of model predictive control (MPC) strategy for seasonal thermochemical energy storage system in a district heating network (2024)
Journal Article
Wei, Z., Tien, P. W., Calautit, J., Darkwa, J., Worall, M., & Boukhanouf, R. (2024). Investigation of model predictive control (MPC) strategy for seasonal thermochemical energy storage system in a district heating network. Applied Energy, 376(Part A), Article 124164

This research investigates the integration of model predictive control (MPC) with seasonal thermochemical energy storage systems (STES) within district heating networks, focusing on the Nottingham district heating network as a case study. The primary... Read More about Investigation of model predictive control (MPC) strategy for seasonal thermochemical energy storage system in a district heating network.

A Review of Thermochemical Energy Storage Systems for District Heating in the UK (2024)
Journal Article
Roger-Lund, S., Darkwa, J., Worall, M., Calautit, J., & Boukhanouf, R. (2024). A Review of Thermochemical Energy Storage Systems for District Heating in the UK. Energies, 17(14), Article 3389. https://doi.org/10.3390/en17143389

Thermochemical energy storage (TCES) presents a promising method for energy storage due to its high storage density and capacity for long-term storage. A combination of TCES and district heating networks exhibits an appealing alternative to natural g... Read More about A Review of Thermochemical Energy Storage Systems for District Heating in the UK.

Multi-objective integrated optimization of geothermal heating system with energy storage using digital twin technology (2024)
Journal Article
Guo, Y., Tang, Q., Darkwa, J., Wang, H., Su, W., Tang, D., & Mu, J. (2024). Multi-objective integrated optimization of geothermal heating system with energy storage using digital twin technology. Applied Thermal Engineering, 252, Article 123685. https://doi.org/10.1016/j.applthermaleng.2024.123685

Heat energy storage technology plays a significant role in energy systems, and the various technological solutions brought about by digitalization are especially valuable in the field of energy storage. This article proposes an innovative model based... Read More about Multi-objective integrated optimization of geothermal heating system with energy storage using digital twin technology.

A novel prediction model for integrated district energy system based on secondary decomposition and artificial rabbits optimization (2024)
Journal Article
Guo, Y., Tang, Q., Darkwa, J., Duan, X., Su, W., Jia, M., & Mu, J. (2024). A novel prediction model for integrated district energy system based on secondary decomposition and artificial rabbits optimization. Energy and Buildings, 310, Article 114106. https://doi.org/10.1016/j.enbuild.2024.114106

Energy predictions for buildings are the basis for energy efficiency and the implementation of smart technologies to cope with operational and energy planning issues in buildings, playing a crucial role in the implementation of environmental protecti... Read More about A novel prediction model for integrated district energy system based on secondary decomposition and artificial rabbits optimization.

Introducing a novel method for simulating stochastic movement and occupancy in residential spaces using time-use survey data (2023)
Journal Article
Zhang, R., Zhou, T., Ye, H., & Darkwa, J. (2024). Introducing a novel method for simulating stochastic movement and occupancy in residential spaces using time-use survey data. Energy and Buildings, 304, Article 113854. https://doi.org/10.1016/j.enbuild.2023.113854

In the context of growing concerns over energy consumption and sustainability, accurate modelling of occupancy patterns within residential buildings is critical. In this study, a novel stochastic occupancy model is introduced for simulating human beh... Read More about Introducing a novel method for simulating stochastic movement and occupancy in residential spaces using time-use survey data.

Enhancement of thermal and mechanical properties of microencapsulated phase change materials with graphene oxide (2023)
Journal Article
Hu, M., Wang, D., Kokogiannakis, G., Darkwa, J., Li, Y., Wang, L., Xu, Q., & Su, W. (2024). Enhancement of thermal and mechanical properties of microencapsulated phase change materials with graphene oxide. Chemical Engineering Journal, 479, Article 147855. https://doi.org/10.1016/j.cej.2023.147855

The low thermal conductivity of microencapsulated phase change materials (MEPCMs) limits the latent heat charging and discharging rates for various applications. To overcome this limitation, we prepared MEPCM by co-surfactants of polyvinyl alcohol an... Read More about Enhancement of thermal and mechanical properties of microencapsulated phase change materials with graphene oxide.

The effect of nucleating agent on the multiphase change materials for energy storage in buildings (2023)
Journal Article
Sinaga, R., Darkwa, J., Worall, M., & Su, W. (2024). The effect of nucleating agent on the multiphase change materials for energy storage in buildings. Applied Thermal Engineering, 239, Article 122153. https://doi.org/10.1016/j.applthermaleng.2023.122153

Phase change materials (PCMs) have the potential to be used for widespread energy storage applications in buildings. However, available PCMs can only function at fixed phase transitional temperatures, restricting their seasonal applicability. To this... Read More about The effect of nucleating agent on the multiphase change materials for energy storage in buildings.

Development of Composite Microencapsulated Phase Change Materials for Multi-Temperature Thermal Energy Storage (2023)
Journal Article
Su, W., Darkwa, J., Zhou, T., Du, D., Kokogiannakis, G., Li, Y., …Gao, L. (2023). Development of Composite Microencapsulated Phase Change Materials for Multi-Temperature Thermal Energy Storage. Crystals, 13(8), Article 1167. https://doi.org/10.3390/cryst13081167

Phase change energy storage materials have been recognized as potential energy-saving materials for balancing cooling and heating demands in buildings. However, individual phase change materials (PCM) with single phase change temperature cannot be ad... Read More about Development of Composite Microencapsulated Phase Change Materials for Multi-Temperature Thermal Energy Storage.

Experimental investigations into thermal performance of phase change emulsion in a fin-and-tube heat exchanger (2023)
Journal Article
Wei, C., Shao, J., & Darkwa, J. (2023). Experimental investigations into thermal performance of phase change emulsion in a fin-and-tube heat exchanger. International Journal of Low-Carbon Technologies, 18, 175–183. https://doi.org/10.1093/ijlct/ctad001

Phase change emulsions (PCMEs) are always identified as potential working fluids that could be used to reduce circulating pump energy consumption in chill water air conditioning systems. But how PCME behaves in a fin-and-tube heat exchanger is still... Read More about Experimental investigations into thermal performance of phase change emulsion in a fin-and-tube heat exchanger.

Solid–Gas Thermochemical Energy Storage Materials and Reactors for Low to High-Temperature Applications: A Concise Review (2023)
Journal Article
Kur, A., Darkwa, J., Calautit, J., Boukhanouf, R., & Worall, M. (2023). Solid–Gas Thermochemical Energy Storage Materials and Reactors for Low to High-Temperature Applications: A Concise Review. Energies, 16(2), Article 756. https://doi.org/10.3390/en16020756

Thermochemical energy storage materials and reactors have been reviewed for a range of temperature applications. For low-temperature applications, magnesium chloride is found to be a suitable candidate at temperatures up to 100 °C, whereas calcium hy... Read More about Solid–Gas Thermochemical Energy Storage Materials and Reactors for Low to High-Temperature Applications: A Concise Review.

Enhancing the detection performance of a vision-based window opening detector (2022)
Journal Article
Tien, P. W., Wei, S., Calautit, J., Darkwa, J., & Wood, C. (2022). Enhancing the detection performance of a vision-based window opening detector. Cleaner Energy Systems, 3, Article 100038. https://doi.org/10.1016/j.cles.2022.100038

In favourable climates and building types, employing natural ventilation can lead to significant energy savings and health benefits. However, in cold climates or conditions, the use of natural ventilation could result in significant heat loss and, co... Read More about Enhancing the detection performance of a vision-based window opening detector.

Parametric study of a novel combination of solar chimney and radiative cooling cavity for natural ventilation enhancement in residential buildings (2022)
Journal Article
Suhendri, S., Hu, M., Su, Y., Darkwa, J., & Riffat, S. (2022). Parametric study of a novel combination of solar chimney and radiative cooling cavity for natural ventilation enhancement in residential buildings. Building and Environment, 225, Article 109648. https://doi.org/10.1016/j.buildenv.2022.109648

The application of radiative cooling (RC) is expanding to a diverse research field, with some current studies trying to apply RC for natural ventilation. One proposed strategy is to use RC for the enhancement of solar chimney (SC) ventilation, and th... Read More about Parametric study of a novel combination of solar chimney and radiative cooling cavity for natural ventilation enhancement in residential buildings.

Experimental Investigation on Compressive Strength, Ultrasonic Characteristic and Cracks Distribution of Granite Rock Irradiated by a Moving Laser Beam (2022)
Journal Article
Kuang, L., Sun, L., Yu, D., Wang, Y., Chu, Z., & Darkwa, J. (2022). Experimental Investigation on Compressive Strength, Ultrasonic Characteristic and Cracks Distribution of Granite Rock Irradiated by a Moving Laser Beam. Applied Sciences, 12(20), Article 10681. https://doi.org/10.3390/app122010681

Efficient fracturing is the key issue for the exploitation of geothermal energy in a Hot Dry Rock reservoir. By using the laser irradiation cracking method, this study investigates the changes in uniaxial compressive strength, ultrasonic characterist... Read More about Experimental Investigation on Compressive Strength, Ultrasonic Characteristic and Cracks Distribution of Granite Rock Irradiated by a Moving Laser Beam.

Enhancement of Syngas Production in Co-Pyro-Gasification of Biomass and Plastic Waste Materials: Computational Study (2022)
Preprint / Working Paper
Darkwa, J., Kwawu, C., Corner, J., Kemausuor, F., Adei, E., Agyekum, K., & Boateng, I. D. Enhancement of Syngas Production in Co-Pyro-Gasification of Biomass and Plastic Waste Materials: Computational Study

The process of co-pyro-gasification of biomass and plastics appears to have the potential for increasing syngas production for power generation and thus minimizing the impact of plastic waste on the environment. This study was based on co-pyro-gasifi... Read More about Enhancement of Syngas Production in Co-Pyro-Gasification of Biomass and Plastic Waste Materials: Computational Study.

Evaluating urban heat island mitigation strategies for a subtropical city centre (a case study in Osaka, Japan) (2022)
Journal Article
Zheng, T., Qu, K., Darkwa, J., & Calautit, J. K. (2022). Evaluating urban heat island mitigation strategies for a subtropical city centre (a case study in Osaka, Japan). Energy, 250, Article 123721. https://doi.org/10.1016/j.energy.2022.123721

Urban heat island (UHI) effects were first observed in London in the 19th century. The urban heat island is identified by developing higher temperatures in urban areas than the surrounding rural areas that directly surround them. However, there are s... Read More about Evaluating urban heat island mitigation strategies for a subtropical city centre (a case study in Osaka, Japan).

The microencapsulation, thermal enhancement, and applications of medium and high-melting temperature phase change materials: A review (2022)
Journal Article
Sinaga, R., Darkwa, J., Omer, S. A., & Worall, M. (2022). The microencapsulation, thermal enhancement, and applications of medium and high-melting temperature phase change materials: A review. International Journal of Energy Research, 46(8), 10259-10300. https://doi.org/10.1002/er.7860

Microencapsulated phase change materials (MEPCMs) have made tremendous advancements in recent years, owing to their increased demand for a variety of energy storage applications. In this paper, current microencapsulation techniques, enhancement, and... Read More about The microencapsulation, thermal enhancement, and applications of medium and high-melting temperature phase change materials: A review.

Prospects of Bioenergy Production for Sustainable Rural Development in Ghana (2021)
Journal Article
Nelson, N., Darkwa, J., & Calautit, J. (2021). Prospects of Bioenergy Production for Sustainable Rural Development in Ghana. Journal of Sustainable Bioenergy Systems, 11(04), 227-259. https://doi.org/10.4236/jsbs.2021.114015

Biomass supplies about 80% of the energy needs for cooking and heating in rural Ghana. It is predominantly used in traditional and inefficient forms (firewood and charcoal), which presents environmental and health concerns. In order to better the liv... Read More about Prospects of Bioenergy Production for Sustainable Rural Development in Ghana.

Real-time monitoring of occupancy activities and window opening within buildings using an integrated deep learning-based approach for reducing energy demand (2021)
Journal Article
Tien, P. W., Wei, S., Calautit, J. K., Darkwa, J., & Wood, C. (2022). Real-time monitoring of occupancy activities and window opening within buildings using an integrated deep learning-based approach for reducing energy demand. Applied Energy, 308, Article 118336. https://doi.org/10.1016/j.apenergy.2021.118336

Occupancy behaviour in buildings can impact the energy performance and operation of heating, ventilation and air-conditioning (HVAC) systems. HVAC, which uses conventional control strategies or “fixed” setpoint schedules, could not adjust to the cond... Read More about Real-time monitoring of occupancy activities and window opening within buildings using an integrated deep learning-based approach for reducing energy demand.

The impact of thermal insulation on cooling energy consumption and optimal insulation thickness for underground tunnel (2021)
Journal Article
Wang, Y., Wang, C., Gao, S., Zheng, X., & Darkwa, J. (2021). The impact of thermal insulation on cooling energy consumption and optimal insulation thickness for underground tunnel. Sustainable Energy Technologies and Assessments, 47, Article 101495. https://doi.org/10.1016/j.seta.2021.101495

The provision of mechanical cooling in deep mines comes with a significant energy cost as a significant amount of heat transfers from surrounding rock to the airflow. Thermal insulation can be applied to reduce such heat transfer, thereby cutting dow... Read More about The impact of thermal insulation on cooling energy consumption and optimal insulation thickness for underground tunnel.

A deep learning approach towards the detection and recognition of opening of windows for effective management of building ventilation heat losses and reducing space heating demand (2021)
Journal Article
Tien, P. W., Wei, S., Liu, T., Calautit, J., Darkwa, J., & Wood, C. (2021). A deep learning approach towards the detection and recognition of opening of windows for effective management of building ventilation heat losses and reducing space heating demand. Renewable Energy, 177, 603-625. https://doi.org/10.1016/j.renene.2021.05.155

Building ventilation accounts for up to 30% of the heat loss in commercial buildings and 25% in industrial buildings. To effectively aid the reduction of energy consumption in the building sector, the development of demand-driven control systems for... Read More about A deep learning approach towards the detection and recognition of opening of windows for effective management of building ventilation heat losses and reducing space heating demand.

Experimental investigation on performance improvement of thermoelectric generator based on phase change materials and heat transfer enhancement (2021)
Journal Article
Wang, Y., Peng, Y., Guo, K., Zheng, X., Darkwa, J., & Zhong, H. (2021). Experimental investigation on performance improvement of thermoelectric generator based on phase change materials and heat transfer enhancement. Energy, 229, Article 120676. https://doi.org/10.1016/j.energy.2021.120676

Thermoelectric application has been widely researched due to its various advantages. Its use has been limited to niche industrial applications and exploratory research development due to the poor economic viability. It is essential to achieve the opt... Read More about Experimental investigation on performance improvement of thermoelectric generator based on phase change materials and heat transfer enhancement.

Experimental Data on Water Vapour Adsorption on Silica Gel in Fully Packed and Z-Annulus Packed Beds (2021)
Journal Article
Yeboah, S. K., & Darkwa, J. (2021). Experimental Data on Water Vapour Adsorption on Silica Gel in Fully Packed and Z-Annulus Packed Beds. Data in Brief, 34, Article 106736. https://doi.org/10.1016/j.dib.2021.106736

Experimental data on water vapour adsorption on silica gel in four packed bed configurations namely fully packed bed (FPB), large annulus packed bed (LAPB), medium annulus packed bed (MAPB) and small annulus packed bed (SAPB) are presented. Raw tempe... Read More about Experimental Data on Water Vapour Adsorption on Silica Gel in Fully Packed and Z-Annulus Packed Beds.

Potential of Bioenergy in Rural Ghana (2021)
Journal Article
Nelson, N., Darkwa, J., Calautit, J., Worall, M., Mokaya, R., Adjei, E., …Ahiekpor, J. (2021). Potential of Bioenergy in Rural Ghana. Sustainability, 13(1), Article 381. https://doi.org/10.3390/su13010381

Crop residues are common in rural Ghana due to the predominant role agriculture plays in livelihood activities in these communities. In this paper we investigate the prospects of exploiting agricultural crop residues for rural development in Ghana th... Read More about Potential of Bioenergy in Rural Ghana.

Development of TiO2/RT–35HC based nanocomposite phase change materials (NCPCMs) for thermal management applications (2020)
Journal Article
Arshad, A., Jabbal, M., Shi, L., Darkwa, J., Weston, N. J., & Yan, Y. (2021). Development of TiO2/RT–35HC based nanocomposite phase change materials (NCPCMs) for thermal management applications. Sustainable Energy Technologies and Assessments, 43, Article 100865. https://doi.org/10.1016/j.seta.2020.100865

This experimental study covers the development of novel nanocomposite phase change materials (NCPCMs) based on RT–35HC as a phase change material (PCM) and titanium oxide (TiO2) as thermal conductivity enhancement material, for thermal management app... Read More about Development of TiO2/RT–35HC based nanocomposite phase change materials (NCPCMs) for thermal management applications.

Experimental investigation into the integration of solid desiccant packed beds with oscillating heat pipes for energy efficient isothermal adsorption processes (2020)
Journal Article
Yeboah, S. K., & Darkwa, J. (2021). Experimental investigation into the integration of solid desiccant packed beds with oscillating heat pipes for energy efficient isothermal adsorption processes. Thermal Science and Engineering Progress, 21, Article 100791. https://doi.org/10.1016/j.tsep.2020.100791

The heat of adsorption released during physical adsorption of water vapour on solid desiccants increases its surface vapour pressure consequently decreasing its adsorption capacity. In packed beds, this raises the bed temperature subsequently increas... Read More about Experimental investigation into the integration of solid desiccant packed beds with oscillating heat pipes for energy efficient isothermal adsorption processes.

Implementation of Passive Radiative Cooling Technology in Buildings: A Review (2020)
Journal Article
Suhendri, S., Hu, M., Su, Y., Darkwa, J., & Riffat, S. (2020). Implementation of Passive Radiative Cooling Technology in Buildings: A Review. Buildings, 10(12), 1-28. https://doi.org/10.3390/buildings10120215

Radiative cooling (RC) is attracting more interest from building engineers and architects. Using the sky as the heat sink, a radiative cooling material can be passively cooled by emitting heat to the sky. As a result of the development of material te... Read More about Implementation of Passive Radiative Cooling Technology in Buildings: A Review.

Experimental data on Helically Coiled Oscillating Heat Pipe (HCOHP) design and thermal performance (2020)
Journal Article
Yeboah, S. K., & Darkwa, J. (2020). Experimental data on Helically Coiled Oscillating Heat Pipe (HCOHP) design and thermal performance. Data in Brief, 33, Article 106505. https://doi.org/10.1016/j.dib.2020.106505

Experimental and derived data from three Helically Coiled Oscillating Heat Pipes (HCOHPs) charged with ethanol, methanol and deionized water working fluids respectively are presented. The data was obtained from prototypes of the HCOHPs fabricated out... Read More about Experimental data on Helically Coiled Oscillating Heat Pipe (HCOHP) design and thermal performance.

Performance comparison of two solar cooking storage pots combined with wonderbag slow cookers for off-sunshine cooking (2020)
Journal Article
Mawire, A., Lentswe, K., Owusu, P., Shobo, A., Darkwa, J., Calautit, J., & Worall, M. (2020). Performance comparison of two solar cooking storage pots combined with wonderbag slow cookers for off-sunshine cooking. Solar Energy, 208, 1166-1180. https://doi.org/10.1016/j.solener.2020.08.053

Two similar storage cooking pots are experimentally evaluated and compared during solar cooking and storage off-sunshine cooking periods. One storage pot has sunflower oil as the sensible heat storage material, while the other has erythritol as the p... Read More about Performance comparison of two solar cooking storage pots combined with wonderbag slow cookers for off-sunshine cooking.

Experimental study of thermal fracturing of Hot Dry Rock irradiated by moving laser beam: Temperature, efficiency and porosity (2020)
Journal Article
Wang, Y., Jiang, J., Darkwa, J., Xu, Z., Zheng, X., & Zhou, G. (2020). Experimental study of thermal fracturing of Hot Dry Rock irradiated by moving laser beam: Temperature, efficiency and porosity. Renewable Energy, 160, 803-816. https://doi.org/10.1016/j.renene.2020.06.138

A new laser irradiation fracturing method is employed to crack the Hot Dry Rock (HDR) and variations of rock temperature, specific energy (SE) and modified specific energy (MSE), thermal damages and open porosity of granite samples caused by moving l... Read More about Experimental study of thermal fracturing of Hot Dry Rock irradiated by moving laser beam: Temperature, efficiency and porosity.

Thermo-mechanical and moisture absorption properties of fly ash-based lightweight geopolymer concrete reinforced by polypropylene fibers (2020)
Journal Article
Wang, Y., Zheng, T., Zheng, X., Liu, Y., Darkwa, J., & Zhou, G. (2020). Thermo-mechanical and moisture absorption properties of fly ash-based lightweight geopolymer concrete reinforced by polypropylene fibers. Construction and Building Materials, 251, Article 118960. https://doi.org/10.1016/j.conbuildmat.2020.118960

An experimental investigation on the thermo-mechanical and moisture absorption properties of lightweight geopolymer concrete prepared with fly ash, NaOH, sodium silicate and Polypropylene Fibers (PF) is presented in this study. The effects of dry den... Read More about Thermo-mechanical and moisture absorption properties of fly ash-based lightweight geopolymer concrete reinforced by polypropylene fibers.

Minimizing heat transmission loads and improving energy efficiency of building envelopes in sub-Saharan Africa using bio-based composite materials (2020)
Journal Article
Opoku, R., Obeng, G. Y., Darkwa, J., & Kwofie, S. (2020). Minimizing heat transmission loads and improving energy efficiency of building envelopes in sub-Saharan Africa using bio-based composite materials. Scientific African, 8, Article e00358. https://doi.org/10.1016/j.sciaf.2020.e00358

Increasing effect of climate change coupled with global warming has necessitated the need for mechanical cooling in buildings to provide indoor thermal comfort. Many countries in tropical climates, particularly in sub-Saharan Africa, use sandcrete bl... Read More about Minimizing heat transmission loads and improving energy efficiency of building envelopes in sub-Saharan Africa using bio-based composite materials.

Microencapsulation of Paraffin with Poly (Urea Methacrylate) Shell for Solar Water Heater (2019)
Journal Article
Su, W., Li, Y., Zhou, T., Darkwa, J., Kokogiannakis, G., & Li, Z. (2019). Microencapsulation of Paraffin with Poly (Urea Methacrylate) Shell for Solar Water Heater. Energies, 12(18), Article 3406. https://doi.org/10.3390/en12183406

Previous research has demonstred that microencapsulated phase change materials (MEPCMs) could significantly increase the energy storage density of solar thermal energy storage (TES) systems. Compared with traditional phase change materials (PCMs), ME... Read More about Microencapsulation of Paraffin with Poly (Urea Methacrylate) Shell for Solar Water Heater.

Numerical thermal evaluation of laminated binary microencapsulated phase change material drywall systems (2019)
Journal Article
Su, W., Darkwa, J., & Kokogiannakis, G. (2020). Numerical thermal evaluation of laminated binary microencapsulated phase change material drywall systems. Building Simulation, 13, 89-98. https://doi.org/10.1007/s12273-019-0563-z

Microencapsulated phase change materials (MEPCMs) have the potential for energy storage applications in buildings. However, current MEPCMs are limited by their singular phase change transitional temperatures and are therefore unable to satisfy all ye... Read More about Numerical thermal evaluation of laminated binary microencapsulated phase change material drywall systems.

Phase Change Material Blind System for Double Skin Façade Integration: System Development and Thermal Performance Evaluation (2019)
Journal Article
Li, Y., Darkwa, J., Kokogiannakis, G., & Su, W. (2019). Phase Change Material Blind System for Double Skin Façade Integration: System Development and Thermal Performance Evaluation. Applied Energy, 252, 1-17. https://doi.org/10.1016/j.apenergy.2019.113376

Double skin facades (DSFs) are often applied as energy reducing elements in modern buildings, but do experience overheating problems in warm seasons which may contribute to increase in cooling loads. There are currently various thermal management dev... Read More about Phase Change Material Blind System for Double Skin Façade Integration: System Development and Thermal Performance Evaluation.

The micro‐/nano‐PCMs for thermal energy storage systems: A state of art review (2019)
Journal Article
Arshad, A., Jabbal, M., Yan, Y., & Darkwa, J. (2019). The micro‐/nano‐PCMs for thermal energy storage systems: A state of art review. International Journal of Energy Research, 43(11), 5572-5620. https://doi.org/10.1002/er.4550

With advancement in technology, the nanotechnology, various thermal energy storage (TES) materials have been invented and modified with promising thermal transport properties. The solid–liquid phase change materials (PCMs) have been extensively used... Read More about The micro‐/nano‐PCMs for thermal energy storage systems: A state of art review.

A numerical and experimental analysis of an integrated TEG-PCM power enhancement system for photovoltaic cells (2019)
Journal Article
Darkwa, J., Calautit, J., Du, D., & Kokogianakis, G. (2019). A numerical and experimental analysis of an integrated TEG-PCM power enhancement system for photovoltaic cells. Applied Energy, 248, 688-701. https://doi.org/10.1016/j.apenergy.2019.04.147

Solar photovoltaic (PV) cells especially crystal silicon cells have witnessed a soaring installed capacity during past years. Research efforts have been made to increase the PV conversion efficiency and one direction is towards the cooling of PV syst... Read More about A numerical and experimental analysis of an integrated TEG-PCM power enhancement system for photovoltaic cells.

Effect of design parameters on thermal performance of integrated phase change material blind system for double skin façade buildings (2019)
Journal Article
Li, Y., Darkwa, J., Kokogiannakis, G., & Su, W. (2019). Effect of design parameters on thermal performance of integrated phase change material blind system for double skin façade buildings. International Journal of Low-Carbon Technologies, 14(2), 286-293. https://doi.org/10.1093/ijlct/ctz010

Double skin facades (DSFs) have overheating problems in warm seasons which may increase the cooling loads in buildings. A previous study has developed an integrated phase change material (PCM) blind system and proved its capacity of mitigating the ov... Read More about Effect of design parameters on thermal performance of integrated phase change material blind system for double skin façade buildings.

Experimental comparison of green facades with outdoor test cells during a hot humid season (2019)
Journal Article
Kokogiannakis, G., Darkwa, J., Badeka, S., & Li, Y. (2019). Experimental comparison of green facades with outdoor test cells during a hot humid season. Energy and Buildings, 185, 196-209. https://doi.org/10.1016/j.enbuild.2018.12.038

We used outdoor test cells during a hot humid period to analyse the surface temperatures behind the following four types of green walls: a felt layer wall; a planter boxes wall; a direct climbing plants wall, and; an indirect climbing plants wall. We... Read More about Experimental comparison of green facades with outdoor test cells during a hot humid season.

Experimental investigations into the adsorption enhancement in packed beds using Z-Annular flow configuration (2018)
Journal Article
Yeboah, S., & Darkwa, J. (2019). Experimental investigations into the adsorption enhancement in packed beds using Z-Annular flow configuration. International Journal of Thermal Sciences, 136, 121-134. https://doi.org/10.1016/j.ijthermalsci.2018.10.027

Annular packed bed structures have the potential to overcome limitations of conventional fully packed bed types by offering radial distribution of airflow within them to enhance fluid-solid contact during adsorption and also to minimize pressure drop... Read More about Experimental investigations into the adsorption enhancement in packed beds using Z-Annular flow configuration.

Nano-silicon dioxide hydrosol as surfactant for preparation of microencapsulated phase change materials for thermal energy storage in buildings (2018)
Journal Article
Su, W., Darkwa, J., & Kokogiannakis, G. (2018). Nano-silicon dioxide hydrosol as surfactant for preparation of microencapsulated phase change materials for thermal energy storage in buildings. International Journal of Low-Carbon Technologies, https://doi.org/10.1093/ijlct/cty032

Microencapsulated phase change materials (MEPCMs) have been recognized as potential energy storage materials for applications such as balancing of heating and cooling loads in buildings. However, current MEPCMs do suffer from low thermal conductivity... Read More about Nano-silicon dioxide hydrosol as surfactant for preparation of microencapsulated phase change materials for thermal energy storage in buildings.

Thermal performance of a novel helically coiled oscillating heat pipe (HCOHP) for isothermal adsorption: an experimental study (2018)
Journal Article
Yeboah, S., & Darkwa, J. (2018). Thermal performance of a novel helically coiled oscillating heat pipe (HCOHP) for isothermal adsorption: an experimental study. International Journal of Thermal Sciences, 128, https://doi.org/10.1016/j.ijthermalsci.2018.02.014

Helically Coiled Oscillating Heat Pipes (HCOHPs) have been designed and tested under laboratory conditions to investigate their potential to achieve isothermal adsorption when integrated with a cylindrical solid desiccant packed bed system. The HCOHP... Read More about Thermal performance of a novel helically coiled oscillating heat pipe (HCOHP) for isothermal adsorption: an experimental study.

Preparation of microencapsulated phase change materials (MEPCM) for thermal energy storage (2017)
Journal Article
Su, W., Darkwa, J., Kokogiannakis, G., Zhou, T., & Li, Y. (in press). Preparation of microencapsulated phase change materials (MEPCM) for thermal energy storage. Energy Procedia, 121, https://doi.org/10.1016/j.egypro.2017.07.485

Microencapsulated phase change materials (MEPCM) could be used for energy saving applications in buildings due to their relatively high energy storage capacities at constant temperature, which could passively reduce peak cooling loads in summer. In t... Read More about Preparation of microencapsulated phase change materials (MEPCM) for thermal energy storage.

Heat transfer analysis of an integrated double skin façade and phase change material blind system (2017)
Journal Article
Li, Y., Darkwa, J., & Kokogiannakis, G. (2017). Heat transfer analysis of an integrated double skin façade and phase change material blind system. Building and Environment, 125, https://doi.org/10.1016/j.buildenv.2017.08.034

In this study, the heat transfer in an integrated double skin facade (DSF) and phase change material (PCM) blind system has been theoretically analysed. Both heat transfer and airflow models with CFD methods have been developed for the integrated DSF... Read More about Heat transfer analysis of an integrated double skin façade and phase change material blind system.

Multiphase change materials for energy storage application in buildings (2017)
Journal Article
Darkwa, J., & Su, W. (2017). Multiphase change materials for energy storage application in buildings. Journal of Thermophysics and Heat Transfer, 31(4), 791-795. https://doi.org/10.2514/1.T5101

Experimental study has been carried out towards the development of a multiphase change material (MCM) by combining two fabricated microencapsulated phase change materials (MEPCM-oct and MEPCM-eic) samples. The study also covered the characterization... Read More about Multiphase change materials for energy storage application in buildings.

Review of solid–liquid phase change materials and their encapsulation technologies (2017)
Journal Article
Su, W., Darkwa, J., & Kokogiannakis, G. (2017). Review of solid–liquid phase change materials and their encapsulation technologies. Renewable and Sustainable Energy Reviews, 48, https://doi.org/10.1016/j.rser.2015.04.044

Various types of solid–liquid phase change materials (PCMs) have been reviewed for thermal energy storage applications. The review has shown that organic solid–liquid PCMs have much more advantages and capabilities than inorganic PCMs but do possess... Read More about Review of solid–liquid phase change materials and their encapsulation technologies.

Development of microencapsulated phase change material for solar thermal energy storage (2016)
Journal Article
Su, W., Darkwa, J., & Kokogiannakis, G. (2017). Development of microencapsulated phase change material for solar thermal energy storage. Applied Thermal Engineering, 112, https://doi.org/10.1016/j.applthermaleng.2016.11.009

In this paper a novel microencapsulated phase change material (MF-3) has been developed and tested for solar assisted hot water storage systems. Even though the morphology of the sample was affected by the type of emulsifier used for fabrication it r... Read More about Development of microencapsulated phase change material for solar thermal energy storage.

Development of a novel phase change material emulsion for cooling systems (2015)
Journal Article
Shao, J., Darkwa, J., & Kokogiannakis, G. (2016). Development of a novel phase change material emulsion for cooling systems. Renewable Energy, 87, https://doi.org/10.1016/j.renene.2015.10.050

In this paper, a novel phase change material emulsion (PCE-10) consisting of an organic PCM (RT10) and water has been developed. Its thermophysical properties such as heat of fusion, viscosity and sub-cooling temperature have been established. The ch... Read More about Development of a novel phase change material emulsion for cooling systems.

Review of phase change emulsions (PCMEs) and their applications in HVAC systems (2015)
Journal Article
Shao, J., Darkwa, J., & Kokogiannakis, G. (2015). Review of phase change emulsions (PCMEs) and their applications in HVAC systems. Energy and Buildings, 94, https://doi.org/10.1016/j.enbuild.2015.03.003

Phase change material emulsions (PCMEs) are multifunctional fluids consisting of phase change materials (PCMs) and carrier fluids. PCMEs could be potential candidates as heat transfer media in heating, ventilation and air conditioning (HVAC) systems.... Read More about Review of phase change emulsions (PCMEs) and their applications in HVAC systems.

Thermal evaluation of laminated composite phase change material gypsum board under dynamic conditions (2015)
Journal Article
Zhou, T., Darkwa, J., & Kokogiannakis, G. (2015). Thermal evaluation of laminated composite phase change material gypsum board under dynamic conditions. Renewable Energy, 78, https://doi.org/10.1016/j.renene.2015.01.025

Thermal evaluation of non-deform laminated composite phase change material (PCM) gypsum board has been carried out. The theoretical studies covered the analysis of different thicknesses of PCM layers and their corresponding heat transfer rates during... Read More about Thermal evaluation of laminated composite phase change material gypsum board under dynamic conditions.

Evaluation of thermal energy dynamics in a compacted high-conductivity phase-change material (2015)
Journal Article
Darkwa, J., Su, O., & Zhou, T. (2015). Evaluation of thermal energy dynamics in a compacted high-conductivity phase-change material. Journal of Thermophysics and Heat Transfer, 29(2), https://doi.org/10.2514/1.T3911

This study evaluates the concept of developing a nondeform phase-change energy storage material possessing higher thermal conductivity and energy storage density through a pressure compaction process. The theoretical and experimental investigations h... Read More about Evaluation of thermal energy dynamics in a compacted high-conductivity phase-change material.

Simulating Thermochromic and Heat Mirror Glazing Systems in Hot and Cold Climates (2014)
Journal Article
Kokogiannakis, G., Darkwa, J., & Aloisio, C. (2014). Simulating Thermochromic and Heat Mirror Glazing Systems in Hot and Cold Climates. Energy Procedia, 62, 22-31. https://doi.org/10.1016/j.egypro.2014.12.363

This paper investigates the potential energy requirements for heating and cooling when using a thermochromic glazing system on a highly glazed tall office building and comparisons are made with the respective performance of two heat mirror units and... Read More about Simulating Thermochromic and Heat Mirror Glazing Systems in Hot and Cold Climates.

A survey on development of energy service industry in Zhejiang China (2014)
Journal Article
Qu, Y., Wang, X. Y., & Darkwa, J. (in press). A survey on development of energy service industry in Zhejiang China. Applied Mechanics and Materials, 587-589, https://doi.org/10.4028/www.scientific.net/AMM.587-589.140

Energy service industry (ESI) has grown quickly recent year in China. A main and important role in ESI is Energy Service Company (ESCO) which engages in reducing energy consumption through retrofitting the existing facilities. This survey focuses on... Read More about A survey on development of energy service industry in Zhejiang China.

Support for the integration of green roof constructions within Chinese building energy performance policies (2013)
Journal Article
Kokogiannakis, G., & Darkwa, J. (2014). Support for the integration of green roof constructions within Chinese building energy performance policies. Energy, 65, https://doi.org/10.1016/j.energy.2013.11.076

Green roofs could act as a thermal buffer in buildings and offer potential energy savings. However, the energy benefits from green roofs are not usually properly recognised by traditional building energy regulations. Building energy regulations are t... Read More about Support for the integration of green roof constructions within Chinese building energy performance policies.

Simulating the influence of microclimatic design on mitigating the urban heat island effect in the Hangzhou metropolitan area of China (2013)
Journal Article
Shen, T., Chow, D., & Darkwa, J. (2016). Simulating the influence of microclimatic design on mitigating the urban heat island effect in the Hangzhou metropolitan area of China. International Journal of Low-Carbon Technologies, 11(1), https://doi.org/10.1093/ijlct/ctt050

There are many indications that Urban Heat Island (UHI) is a significant contributor to the increased emission of greenhouse gases due to the increase in energy consumption for cooling during summer. Hangzhou is currently the second hottest city in C... Read More about Simulating the influence of microclimatic design on mitigating the urban heat island effect in the Hangzhou metropolitan area of China.

Performance of an integrated solar absorption cooling system in a sub-tropical region (2012)
Journal Article
Darkwa, J., & Fraser, S. (2012). Performance of an integrated solar absorption cooling system in a sub-tropical region. International Journal of Low-Carbon Technologies, 7(3), https://doi.org/10.1093/ijlct/cts024

Evaluation of an integrated solar absorption cooling system located in a sub-tropical region has been carried out. Analysis of the results revealed an operational efficiency of 61% for the solar collectors at a mean differential temperature forumla o... Read More about Performance of an integrated solar absorption cooling system in a sub-tropical region.

Impact of material surface properties on building performance across a variety of climates (2012)
Journal Article
Kokogiannakis, G., Tuohy, P., & Darkwa, J. (2012). Impact of material surface properties on building performance across a variety of climates. International Journal of Low-Carbon Technologies, 7(3), https://doi.org/10.1093/ijlct/cts018

Reflective coatings have been promoted for improved energy performance of buildings and are considered in some building regulations such as the California Title 24 standard. This paper provides an analysis of the energy impact of different internal a... Read More about Impact of material surface properties on building performance across a variety of climates.

The role of green roofs on reducing heating and cooling loads: a database across Chinese climates (2011)
Journal Article
Kokogiannakis, G., Tietje, A., & Darkwa, J. (2011). The role of green roofs on reducing heating and cooling loads: a database across Chinese climates. Procedia Environmental Sciences, 11(B), https://doi.org/10.1016/j.proenv.2011.12.094

This paper aims to use detailed modelling techniques and develop a database for assessing in a quick and easy way the energy performance of green roof designs across a range of Chinese climates. The focus is on heating and cooling loads by calculatin... Read More about The role of green roofs on reducing heating and cooling loads: a database across Chinese climates.

A simulation-based framework for a mapping tool that assesses the energy performance of green roofs
Presentation / Conference Contribution
Kokogiannakis, G., & Darkwa, J. A simulation-based framework for a mapping tool that assesses the energy performance of green roofs.

This paper presents a framework for the development of a GIS open source mapping tool that aims to disseminate a database with results of detailed simulations in order to assess in a quick and easy way the energy performance of green roof designs acr... Read More about A simulation-based framework for a mapping tool that assesses the energy performance of green roofs.