Wasim Saman

• University of South Australia

Escalating energy tariffs and peak cooling demands due to climate change along with expanding use of variable renewable energy supply are presenting new challenges and opportunities for air conditioning system operation and control. This research presents the outcome of an investigation into the use of a thermal battery using salt-hydrate phase cha...

High temperature phase change materials (PCMs) are being proposed as thermal energy storage media in concentrated solar power plants. The thermophysical properties of PCMs, such as the latent heat of fusion/solidification need to be defined to enable system design and evaluate system performance and cost analysis. Several methods have been used to...

In the current study a novel geopolymer created from waste materials (namely fly ash and black slag) has been characterised as a potential high temperature thermal energy storage material option. Several geopolymer samples have been fabricated and characterised by X-ray diffraction (XRD) and scanning electron microscopy (SEM). Additionally, the den...

This study investigates summer indoor temperatures in energy efficient multilevel houses built since 2010 in Adelaide to identify and define overheating during summer months. The method includes three steps: 1) calculating the number of days with top floor maximum daily air temperature above 32 °C during four summers (December-February of 2011–2015...

A numerical heat transfer analysis of the phase change material (PCM) in a high temperature vertical triplex tube thermal energy storage system (TTTESS) was performed, using ANSYS FLUENT 15.0. The model has been validated against experimental data using a low temperature PCM in a TTTESS. The numerical results agree well with experiment. The validat...

Different options of sensible and latent heat storage systems comprising different types of heat transfer fluids, heat storage media or phase change materials (PCMs) have been compared considering the upstream and downstream requirements of a concentrated solar power cycle. For an optimal system, analysis of both the energy efficiency and exergy re...

Space cooling is the main contributor to high electrical power demand in summer. This research investigates the effect of adding a phase change thermal energy storage unit (PCTSU) to an air source heat pump (HP) cooling system. The HP model improves on an existing model in the simulation software library to simulate the HP performance. The PCTSU pe...

Despite the abundant solar insolation in Australia there has not been a matching increase in the use of solar water heaters (SWH). Due to the current relatively cheap price of energy in Australia the upfront costs of an SWH are a strong barrier, especially when installation, plumbing, and roof-strengthening costs are taken into consideration. The m...

Current and newly built buildings will inevitably experience the effects of climate change, therefore, the design and performance of these buildings should consider weather data that includes some of the effects of climate change, instead of only using historical weather data. However, climate change weather data suitable for buildings performance...

In the current study the feasibility of using concentrated solar power (CSP) coupled with thermal energy storage (TES) to displace gas for heating was explored. To assess the feasibility, a numerical model of an air-based encapsulated phase change storage system was developed, validated, optimised, and economically costed. The optimised air-based E...

The thermal behaviour of PCM in different configuration of heat exchangers is analysed for the purpose of design and optimisation of a latent heat thermal energy storage unit. Numerical modelling in conjunction with scale analyses provides a cost effective means to examine the performance of different configurations of latent heat storage systems....

In the current study the feasibility of using solar-based renewables coupled with thermal energy storage (TES) to displace gas for heating was explored. To assess the feasibility, a numerical model of an air-based encapsulated phase change (EPCM) storage system was developed, validated, optimised, and economically costed. The optimised air-based EP...

For design and optimization purposes, understanding the performance characteristics of different configurations of PCM systems during charging and discharging processes is crucial, particularly for thermal storage in CSP. A numerical study using FLUENT has been performed to explore and compare the characteristics and behavior of PCM in different sh...

In the current study pre-formed geopolymer half shells were fabricated from a combination of fly ash and black slag. Five (5) geopolymer shells were filled with a chloride-based phase change material (PCM) with a melting point of 540 °C for use in a high temperature thermal energy storage system (TESS). Additionally, three (3) of these shells conta...

In this chapter cost comparisons of encapsulated phase change materials (EPCMs), coil-in-tank, and heat pipe thermal energy storage systems are reviewed. Due to the increased interest in this field there are a number of studies on the economics of the aforementioned systems. However, in the absence of any commercial-scale systems confident cost est...

In an attempt to solve the poor conductivity and material compatibility issues that are common with phase change materials (PCMs), the encapsulation of these materials is proposed. The encapsulation of the PCM involves the covering of the PCM in a suitable material. This has the benefit of increasing the surface area available for heat transfer (in...

The integration of passive features during the design/construction of sustainable buildings requires thorough modelling at the design stage as some features may have unintended consequences resulting in occupant dissatisfaction, and resulting in the building using more energy to maintain comfort. This paper reports the outcome of an investigation i...

The existing and under construction concentrating solar power (CSP) incorporated the two-tank sensible storage system using molten salt as the storage medium. Compared to sensible heat storage, high temperature latent heat storage using phase change materials (PCMs) can provide a smaller storage system, potentially reducing the cost of thermal stor...

Building energy performance simulations are limited to typical meteorological weather conditions available in simulation software. Such simulations are insufficient for analysing energy performance sensitivity to a range of probable weather conditions. This research presents a method for developing robust meteorological weather data that can be use...

Thermal energy storage (TES) is a critical component in a concentrated solar power (CSP) plant since it is able to provide dispatchability and increase the capacity factor of the plant. Recently the Brayton power cycle using supercritical carbon dioxide (s-CO2) has attracted considerable attention as it allows a higher thermal to electric power con...

The design and optimisation of a latent heat thermal storage system requires knowledge of flow, heat and mass transfer during the melting (charging) and solidification (discharging) processes of high temperature PCMs. Using Fluent, numerical modelling was performed to study the impact of natural convection and turbulence, in the melting process of...

The ‘Beat The Heat!’ project was a project of the Australian Federal Governments ‘Low Income Energy Efficiency Program’ (LIEEP). This project aimed to enhance the resilience and improve the comfort and wellbeing of Adelaide households during South Australias long, hot summers. The installation of ceiling insulation and new air-conditioners in the m...

In the context of reducing household greenhouse gas emissions, in-home energy feedback displays have been trialled as a mechanism to assist households to monitor and change energy-use behaviour. As we move towards technology-rich zero-energy homes, the challenge of managing energy use and electricity generation systems will increase and a new role...

The performance of parallel and counter flow configurations of a shell and tube heat exchanger used as a latent heat thermal storage system was investigated. The comparative analysis of the melting and solidification processes (charging and discharging) in the vertical and horizontal orientations of counter and parallel flow was included in this st...

In the following study cost estimates have been undertaken for an encapsulated phase changematerial (EPCM) packed bed, a packed bed thermocline and a traditional two-tank molten salt system. The effect of various heat transfer fluids (air and molten salt), system configuration (cascade vs one PCM, and direct vs indirect) and temperature difference...

Latent heat storage using phase change materials (PCMs) can be used to store large amounts of energy in a narrow temperature difference during phase transition. The thermophysical properties of PCMs such as latent heat,specific heat and melting and solidification temperature need to be defined at high precision for the design and estimating the cos...

Numerical study for phase change material (PCM) in high temperature vertical triplex tube thermal energy storage system (TTTESS) were performed, using ANSYS FLUENT 15. For validation purposes, numerical modelling of a low temperature PCM was initially conducted and the predicted results were compared with the numerical and experimental data from th...

The search for optimal phase change materials (PCMs) for latent heat thermal energy storage systems (LHTESS) focuses almost exclusively on the properties of the PCM. This neglects the significant contribution of the cost of the containment vessel on the total cost of the LHTESS. Thus, to accurately assess the thermoeconomic performance of various P...

Thermal energy storage in concentrated solar thermal power plants improves the dispatchability and eliminates the miss-match between the energy supply and demand. Recently, considerable attention has been made to latent heat thermal energy storage due to its high energy density per unit mass and volume at nearly constant temperature. This paper pre...

A numerical study has been conducted on a shell and tube latent heat storage system whereby the inlet heat transfer fluid direction is periodically reversed during charging and discharging. The impact of varying the boundary condition at the interface of the tubes carrying the heat transfer fluid and phase change material (PCM) on the evolution of...

This study compares the cost of operating the auxiliary components of an optimised standalone hot water fired absorption chiller, using mains grid electricity and an optimised standalone photovoltaic system. The cheaper source was further compared with using mains electricity to operate a conventional reverse cycle air-air heat pump. Both types of...

A survey has been carried out of graduates and employers working in the sustainable energy (SE) industry in Australia. The aims were to identify the key areas of content to be included in University level SE training and the type of degree structures that are most appropriate for SE professionals. Attention was also directed to the mode of instruct...

The intermittency of renewable energy systems remains one of the major hurdles preventing a large scale uptake of these technologies and concentrated solar power (CSP) systems are no different. However, CSP has the benefit of being able to store excess heat using thermal energy storage (TES). For the uptake of CSP with TES it must be demonstrated t...

Electricity grid capacity is often oversized to ensure it accommodates maximum anticipated peak demand. In South Australia, 25% of the grid capacity is required for less than 1% of the time. To reflect the cost of peak demand in electricity tariffs, demand tariffs consider not only electrical energy consumption (kWh), but also electrical power dema...

Deploying standalone solar air-conditioning systems in residential buildings forms a radical demand-side energy management solution for eliminating the peak electricity demand from residential air-conditioning. For existing grids to meet this demand a correspondingly major investment is required to extend the capacity of the infrastructure. For any...

The increased penetration of residential air-conditioners (AC); specifically vapor compression types, is regarded as one of the foremost causes of a dramatic rise in critical peak electricity demands requiring corresponding upgrades of electricity infrastructures. These upgrades requires heavy investments, consequently, driving up electricity price...

In an effort to reduce the cost of thermal energy storage for concentrated solar power plants, a thermocline storage concept was investigated. Two systems were investigated being a sensible-only and an encapsulated phase change system. Both systems have the potential to reduce the storage tank volume and/or reduce the cost of the filler material, t...

In an effort to reduce the cost and increase the material compatibility of encapsulated phase change materials (EPCMs) a new encapsulated system has been proposed. In the current study a molten salt eutectic of barium chloride (53% wt.), potassium chloride (28% wt.) and sodium chloride (19% wt.) has been identified as a promising candidate for low...

This paper presents the stability and corrosion testing results of a candidate high temperature phase change material (PCM) for potential use in concentrating solar power applications. The investigated PCM is a eutectic mixture of NaCl and Na 2CO3 and both are low cost materials. This PCM has a melting temperature of 635 °C and a relatively high la...

Numerical study of inward and outward melting of a high temperature PCM in cylindrical enclosures were performed, using FLUENT 15. For validation purposes, numerical modeling of inward melting of a low temperature PCM was initially conducted and the predicted results were compared with the experimental data from the literature. The validated model...

When compared with other energy storage methods, thermal storage offers a cheap solution for storing energy. A large amount of thermal energy can be stored at the phase transition temperature of phase change materials (PCMs). The thermophysical properties of PCMs are an important factor in designing latent heat thermal storage systems. Thermophysic...

The aim of this study is to better understand the external and internal drivers that affect residential air-conditioning (A/C) use decisions and occupant comfort. Field observations were carried out using instrumental measurements and smartphone questionnaires, recording householder’s A/C usage patterns, indoor/outdoor climatic factors, perception...

A key drawback of using latent heat thermal storage systems for concentrating solar thermal power plants is the low thermal conductivity of the phase change material during the melting and solidification processes. This paper investigates an approach for reducing the thermal resistance by utilising axially finned heat pipes. A numerical model simul...

A concentrating solar power (CSP) system converts sunlight into a heat source which can be used to drive a conventional power plant. Thermal energy storage (TES) improves the dispatchability of a CSP plant. Heat can be stored in either sensible, latent or thermochemical storage. Commercial deployment of CSP systems have been achieved in recent year...

Electricity grid capacity is often oversized compared to average demand to accommodate for peak demands. In South Australia, 25% of the grid capacity is required for less than 1% of the time. To reflect the cost of peak demand in electricity tariffs, peak demand tariffs consider not only electricity consumption (kWh), but also electricity demand (k...

This paper presents the thermo-physical properties and stability testing results of six high-temperature phase-change candidate materials for potential use as a cascaded storage system for concentrating solar power applications. This type of storage is a promising technology because it offers a higher utilization of the possible phase change and a...

The use of water-efficient appliances and inclusion of alternative water sources in urban residential developments is becoming increasingly necessary to meet the growing demands on conventional urban water supplies. As an initiative commissioned by the South Australian State Government in 2009, Lochiel Park is a recent model designed to embrace sus...

The paper demonstrates the profiles of electricity consumption in the low energy housing sector using various time frames, and provides a solid basis for energy estimation by analysing actual 12 month electricity data from 60 comprehensively monitored low energy houses in Australia's leading sustainable green village (Lochiel Park), located in Sout...

Building energy policy in many countries is firmly pointed towards a need for net zero energy homes. But given the limited range of operational energy impacts that can be directly influenced by building regulations, and the wide variation in energy use behaviours of building users, what system performance levels will be required to ensure new homes...

This paper describes the design, construction and initial experimental performance testing of a novel integrated solar thermal system prototype for the provision of space cooling and dehumidification, space heating and domestic water heating. The integrated system aims to replace and duplicate the performance of conventional vapour compression air...

This paper presents a new TRNSYS model of a refrigeration system incorporating phase change material (PCM) for mobile transport. The PCTSU is charged by an off-vehicle refrigeration unit and the PCM provides cooling when discharging and the cooling released is utilized to cool down the refrigerated space. The advantage of this refrigeration system...

Climate change is leading to an increased frequency and severity of heat waves in many parts of the world. This chapter presents some of the findings of a multidisciplinary research project that set out to develop a framework to evaluate the potential impacts of heat waves in Australia. It also presents a technical, social and economic approach to...

With policy directions firmly moving towards net zero energy homes, what do we know about the perceptions and experiences of households who already live in homes at or near that standard? The research sets out to determine whether householders believe these buildings are thermally comfortable, and if they feel confident operating the smart technolo...

Current climate predictions are showing that Australia can expect warmer summers and increased number and severity of heat waves. This changing climate has significant implications for the design of buildings and air conditioning systems. The paper demonstrates that Australia will move to being a cooling dominated continent with a higher number of...

Many countries are searching for ways to reduce the energy and carbon impact of housing. The terms net zero-energy home and net zero-carbon home have entered the policy lexicon, without clear definitions and without widespread understanding of the likely policy impact. Is the concept limited to bespoke architect driven buildings for specific green...

The development of a framework for defining net zero energy and net zero carbon homes has seen significant progress over the past decade. With anthropogenic climate change the principal driver, numerous governments are moving to regulate homes at or near a net zero energy or net zero carbon performance level. What has been missing in the literature...

Energy use in residential buildings is a significant contributor to global carbon emissions. The South Australian Government responded to concern for anthropogenic greenhouse gas emissions by creating a model development of near zero energy homes in a near zero carbon impact estate. The creation of the Lochiel Park Green Village challenged a collec...

The concept of net zero energy and zero emission home has been a goal for those involved in the sustainable building industry. It is now becoming a reality in many parts of the world with an integrated approach of passive design, energy efficient appliances and local renewable generation. The paper describes the activities in Australia focussing on...

Photovoltaic/thermal (PVT) systems generate electrical and thermal energy. In summer, the usage of the collected heat is limited to domestic hot water heating. By contrast in winter, more useful heat collection is favorable, however, the PVT collectors require less cooling; therefore, the improved electrical output is limited. In this paper a new o...

Designing a cost-effective phase change thermal storage system involves two challenging aspects: one is to select a suitable storage material and the other is to increase the heat transfer between the storage material and the heat transfer fluid as the performance of the system is limited by the poor thermal conductivity of the latent heat storage...

An innovative refrigeration system incorporating phase change material (PCM) is proposed to maintain refrigerated trucks at the desired thermal conditions. The advantage of using PCM to maintain low temperatures is that a conventional refrigeration system does not have to be located on-board the vehicle. In addition, the system consumes less energy...

Integrating passive systems such as cross and stack ventilation, a solar chimney, a wind tower or an earth-air tunnel into a building envelope has the potential to significantly reduce the ventilation and air-conditioning demand on buildings. However the application of combination of these features in low rise contemporary buildings is limited. Amo...

The housing sector in Australia has an escalating share of the national energy consumption. Along with other sectors, the need to reduce energy and greenhouse gas emission in dwellings has been under the spotlight in the last decade. Policy drivers for achieving the desired reduction has comprised progressively more stringent regulations for energy...

This paper presents the results of a thermal performance analysis of a phase change thermal storage unit. The unit consists of several parallel flat slabs of phase change material (PCM) with a liquid heat transfer fluid (HTF) flowing along the passages between the slabs. A validated numerical model developed previously to solve the phase change pro...

A one-dimensional liquid-based model for a flat slab phase change thermal storage unit was developed. The model allows for varying wall temperatures along the direction of flow and integrates a convective boundary layer using a previously developed algorithm, which is employed to iteratively calculate the liquid fraction and the temperature of each...

Desiccant/evaporative cooling systems offer an environmentally benign alternative to conventional vapor compression chillers. A desiccant wheel is the heart of this heat driven cooling system and it uses a solid desiccant for dehumidification with silica gel being the most widely used. Proper design of the wheel is important for the successful oper...

A thermal analysis of a solar still type greenhouse integrated desalination unit was carried out for Adelaide’s climatic conditions. A thermal model of a conventional solar still was simulated and the fresh water production of the system was evaluated. The results were compared with previous experimental results. The results demonstrated that even...

This paper presents the results of a comprehensive numerical study on the thermal performance of an air based phase change thermal storage unit (TSU) for space heating. The unit is designed for integration into space heating and cooling systems. The unit consists of a number of one dimensional phase change material (PCM) slabs contained in a rectan...

An experimental investigation was undertaken in which the thermal resistance for the heat flow through a typical timber framed pitched roofing system was measured under outdoor conditions for heat flow up. The measured thermal resistance of low resistance systems such as an uninsulated attic space and a reflective attic space compared well with pub...

This paper investigates the inclusion of passive airflow components such as solar chimney, and wind induced earth air tunnel into a coupled multi-zone ventilation and thermal model. Existing commercial coupled multi-zone ventilation and thermal modelling software do not include passive airflow components, which need a simultaneous prediction of tem...

Low energy systems such as earth-air tunnels (EAT) and evaporative coolers are effective ways of reducing the energy demand for building ventilation and cooling. Direct evaporative coolers are effective in regions of low humidity. Their performance can be enhanced by coupling them to an EAT as pre-coolers. The reliance on electrical fan power can b...

A simple yet accurate iterative method for solving a one-dimensional phase change problem with convection boundary is described. The one-dimensional model takes into account the variation in the wall temperature along the direction of the flow as well as the sensible heat during preheating/pre-cooling of the phase change material (PCM). The mathema...

A number of mathematical models has been developed to predict the heat and mass transfer behavior of moisture transport in air dehumidification applications, with rotary desiccant wheels. A complete model would account for the following mechanisms of transport. 1. convective transport of heat and moisture between the air and the desiccant surface (...

The thermal performance of a PCM thermal storage unit (TSU) is studied numerically and experimentally. The TSU under analysis consists of several flat slabs of phase change material (PCM) with melting temperature of-26.7 °C. Liquid heat transfer fluid (HTF) passes between the slabs to charge and discharge the storage unit. A one dimensional mathema...

Australian climate is characterised by its more sunny days with mild winter condition compared to Europe. Solar water heating systems have been in the market for many years to provide domestic hot water to main cities in Australia. The market for these systems have been constantly growing and relevant Australian Standards have been developed. This...

Passive design combined with energy efficient appliances and active solar systems have been implemented in many new house designs. However their impact on the electrical grid has not been sufficiently documented. A new housing development at Lochiel Park, Adelaide, Australia, is being constructed using a number of passive, active and demand side ma...

Jet impingement is effective at improving the heat transfer between air and a heated surface. Studies have shown that jet impingement can marginally improve the thermal efficiency of a glazed collector. However, little attention has been placed on applying jet impingement to an unglazed solar air collector. This paper presents a theoretical and exp...

Solar assisted air conditioning systems using liquid desiccants represent a promising option to decrease high summer energy demand caused by electrically driven vapor compression machines. The main components of liquid desiccant systems are absorbers and regenerators. However, high efficient and validated reliable components are required and the de...

Solar assisted air conditioning systems using liquid desiccants represent a promising option to decrease high summer energy demand caused by electrically driven vapor compression machines. The main components of liquid desiccant systems are absorbers for dehumidifying and cooling of supply air and regenerators for concentrating the desiccant. Howev...

The South East Asian region is characterised by its high humidity and low variation of outdoor air temperatures all year round. Conventional vapour compression systems have served to provide thermal comfort for the well off residents in this region. These systems, however, have often been associated with less satisfactory attainment of thermal comf...

Numerical analysis of melting and freezing of a PCM thermal storage unit (TSU) with varying wall temperature is presented. The TSU under analysis consists of several layers of thin slabs of a PCM subjected to convective boundary conditions where air flows between the slabs. The model employed takes into account the variations in wall temperature al...

Thermal performance of a roof integrated solar air heating system (RISHS) incorporating phase change material (PCM) thermal storage is analysed. The system provides space heating for a typical South Australian home during the heating period. The system consists of a glazed collector unit integrated into the steel roof of the house and a PCM thermal...

Solar space heating is a proven effective method to reduce conventional energy requirements for domestic heating. However producing a low cost collector design which is commercially viable has been difficult. Research has been conducted into using a corrugated steel roof to function as an unglazed air collector. This research revealed that, althoug...

The provision of energy for households is a major contributor to greenhouse gas emissions in the domestic sector. There is significant scope for energy savings and thus emission reduction in this sector. This paper constructs a bridge between thermal analysis and environmental assessment in the occupancy stage of the dwelling life cycle, approachin...

One of the main components of a liquid desiccant cooling system is the regenerator. In a liquid desiccant air conditioner, outside air is dehumidified by liquid desiccant and cooled within the absorber. The diluted desiccant solution thus obtained has to be concentrated for reuse, by passing through the regenerator and the cycle is, consequently, r...

The thermal and dehumidification behaviour of a standard cross-flow type plate heat exchanger, intended for use as a dehumidifier/cooler, has been investigated both experimentally and numerically. Three sets of experiments have been carried out where air is blown into the primary and secondary sides of the exchanger, while water and liquid desiccan...

A forced flow solar collector/regenerator is one of the effective ways of regenerating the weak liquid solution in an open cycle liquid desiccant air conditioner using solar energy. In this system, the weak solution flows over the absorber plate of a tilted collector/regenerator as a thin liquid film. The forced air stream, which flows parallel or...