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Vertical greening solutions such as direct greening are gaining popularity due to their relatively low cost and minimal ground footprint. However, concerns about increases in relative humidity (RH) can reduce implementation.\ud The impact of several widely-used plant species (Hedera helix, Parthenocissus tricuspidata and Pileostegia viburnoides) on the internal/external temperature and RH on the south-facing wall of replicated experimental model ‘buildings’ was studied during summer and winter. All plant species reduced the air temperature internally/externally during the summer daytimes by at least 1 oC compared to bare ‘buildings’. Hedera produced the greatest cooling effect internally and externally, by 7.2 oC and 5.7 oC respectively. All plant species reduced daily variation in external RH and external/internal temperature during summer; Hedera reduced variation most and Pileostegia least. During night-time in both seasons, the temperature behind Hedera foliage typically remained higher, which could reduce the risk of freeze-thaw damage in winter. \ud The RH was not significantly elevated by vegetation except during warm afternoons in summer and winter. During warm afternoons, the external RH was significantly higher only behind the Hedera foliage compared to the bare ‘buildings’, 11% and 3.7% , summer and winter respectively. However, inside all vegetated ‘buildings’ the RH was at least 11% higher compared to the bare ‘buildings’ during summer. Yet, in winter the internal RH was 5.7% lower in the Hedera-covered compared to the bare ‘buildings’. Current building standards would prevent the transfer of external RH in this range internally, as the walls include protective layers such as damp-proof membranes.

Occupants’ thermal comfort and their adaptation behaviors are essential aspects of building design and energy operation. There is a growing need to better understand the impact of seasonal variation on occupants’ dynamic thermal comfort which provides evidence for building energy flexible design and management. The aim of this study is to investigate the interaction between occupants’ thermal sensation and adaptive behavior in office buildings. Such understanding can provide detailed adaptation rules of human behavior in dynamic office buildings and quantify energy demands. In this study, a framework of a tracking method is proposed, which combines data collection (continuous monitoring of environmental parameters and daily questionnaire surveys), time boundary division and data analysis. Using the tracking method, field surveys were carried out in three mixed-mode office buildings in Chongqing, China. The time-series data was analyzed based on the indoor operative temperature under free-running conditions and five seasonal periods are classified i.e. Latter Spring (LS), Early Cooling period (EC), Middle Cooling period (MC), Latter Cooling period (LC) and Early Autumn (EA). Results show that for the same outdoor temperatures in different seasons, occupants’ clothing insulation varied, indicating that the occupants were more sensitive to environmental changes in EA than in LS, as well as in EC than in LC. The study that flexible energy operation based on the thermal comfort demand can achieve energy savings compared with fixed temperature.

In this paper, the effect of the Building Integrated Photovoltaic (BIPV) system on the building energy demand from the grid is investigated. The main load of the building is due to the Heating, Ventilation and Air-Conditioning (HVAC) equipment, and its load is highly correlated with the ambient temperature. Similarly, the BIPV system output is also dependent on the ambient conditions, and increases with higher solar irradiation but tends to reduce as temperatures decrease when all other factors are constant. BIPV systems, thus, have the potential to help building owners and operators, both from energy production and load reduction/shifting aspects. In this paper, we utilize a 12-month operational data from the BIPV system at Yasar University, and assess its performance from energy generation and demand reduction perspectives.

This research aims to investigate human thermal responses to air humidity in warm and hot environments and to evaluate the effect of humidity on human thermal comfort. 20 subjects were involved in 12 exposure experiments in a well-controlled climate chamber at three relative humidity levels (40%, 60%, 80%) and four air temperature levels (26 °C, 28 °C, 30 °C, 32 °C) with little indoor airflow. The physical environmental and physiological parameters, as well as subjective questionnaires, were collected simultaneously with the on-going experiments. The results show that in hot environments, particularly when the air temperature exceeds 30 °C, the relative humidity has a significant effect on human thermal responses both physiologically and subjectively. The Standard Effective Temperature (SET) is biased when evaluating human thermal comfort in hot-humid environments without considering human thermal adaptation to humidity. Hence, a humidity correction coefficient eRH is proposed to modify the deviation of the SET under different relative humidity levels, and to quantify the effect of humidity on human acceptable air temperatures. The modified acceptable temperature-humidity zone has been obtained using the modified method.

The focus of buildings performance is no longer merely the basic functions of providing shelter or safeguarding human lives and property. Concerns relating to indoor environment quality (IEQ) has increasingly been a topic of interest, mainly in terms of occupants’ comfort and energy consumption. However, these concerns are not often assessed in educational buildings especially sports venues for reasons unknown. This study presents an evaluation of a sports pavilion at University of Reading. IEQ variables, energy consumption and occupancy patterns have been investigated through in-situ measurements which are analysed in comparison with existing benchmark and building energy simulation. The in-situ measurements reflect that the IEQ in the pavilion is considered to be generally satisfactory after comparison with benchmarks. The findings also show that the building has good air-tightness hence high-energy retention. The building was modelled using Integrated Environmental Solutions (IES), a building simulation software. The model verified against metered energy consumption showed a 1.6% deviation. The paper also discussed relevant recommendations to maintain good IEQ and energy efficiency.

The fundamental purpose of a building has evolved from merely providing protection from external environmental climate to more emphasis on integrating building services through building regulations to provide the synergy of comfort, efficiency and safety to the indoor environment. This research recognizes the rising demand and increasing quality of indoor environmental quality (IEQ) in the modern society compared to the acceptable level of previous traditional buildings. Generally due to its varied operations, educational buildings, in this case University libraries have its own set of challenges and barriers such as minimizing damages and decay of books and maintaining indoor conditions with an oversight of providing good IEQ to occupants. This paper presents a detailed evaluation of a 1960s-educational library with 24-hour access at the University of Reading. Through in-situ measurements, modelling and simulations of the building’s energy consumption, IEQ parameters and occupancy patterns, investigations have been performed. Varied scenarios using the Integrated Environmental Solution (IES) software were also investigated. The findings illustrate that due to mixed façade configuration (i.e. sandstone and bricks) there is the unflinching need to balance aesthetics of the facade and functionality of a building to reduce excessive energy use via heating, without compromising on occupant comfort and well-being Although it is envisaged that refurbishing the library building will provide energy savings of up to 40%, this is farfetched and can only be achieved at the detriment of occupant comfort levels as evident in the simulation results, where these savings could not be realised. This paper further discusses the methods, scenarios, and results of ensuring good IEQ, comfort and energy efficiency are not been seen as mutually exclusive. This study forms part of ongoing research into the impact of educational buildings.

Data on electricity consumption patterns relating to different end uses in domestic houses in Botswana is virtually non-existent, despite the fact that the total electricity consumption patterns are available. This can be attributed to the lack of measured and quantified data and in other instances the lack of modern technology to perform such investigations. This paper presents findings from initial studies that are envisaged to bridge the gap. Electricity consumption patterns of 275 domestic households in Gaborone (the capital city of Botswana) have been studied. This was carried out through a questionnaire survey and electricity measurements. Households were categorized based on the number of people occupying the house. From the study, it was evident that the number of people influences the amount of energy a household use although this cannot be treated as an independent factor when assessing energy use. The study also indicated that heating, cooling and domestic hot water (DHW) account for over 30% of energy used in the home. This is worth considering in energy consumption reduction measures. Due to a small sample size, it would not be wise to draw sweeping conclusions from the analysis of this paper or to make statements that would be aimed at influencing policies. However, the results presented forms a formidable base for further research, which is currently on going.

Material complementari del cas estudi "Energy roadmap in Ghana and Botswana", part component del llibre "Case studies for developing globally responsible engineers"

In recent years, computational fluid dynamics (CFD) has been widely used as a method of simulating airflow and addressing indoor environment problems. The complexity of airflows within the indoor environment would make experimental investigation difficult to undertake and also imposes significant challenges on turbulence modelling for flow prediction. This research examines through CFD visualization how air is distributed within a room. Measurements of air temperature and air velocity have been performed at a number of points in an environmental test chamber with a human occupant. To complement the experimental results, CFD simulations were carried out and the results enabled detailed analysis and visualization of spatial distribution of airflow patterns and the effect of different parameters to be predicted. The results demonstrate the complexity of modelling human exhalation within a ventilated enclosure and shed some light into how to achieve more realistic predictions of the airflow within an occupied enclosure.

Environmental building assessment tools have been developed to measure how well or poorly a building is performing, or likely to perform, against a declared set of criteria, or environmental considerations, in order to achieve sustainability principles. Knowledge of environmental building assessment tools is therefore important for successful design and construction of environmentally friendly buildings for countries. The purpose of the research is to investigate the knowledge and level of awareness of environmental building assessment tools among industry practitioners in Botswana. One hundred and seven paper-based questionnaires were delivered to industry practitioners, including architects, engineers, quantity surveyors, real estate developers and academics. Users were asked what they know about building assessment, whether they have used any building assessment tool in the past, and what they perceive as possible barriers to the implementation of environmental building assessment tools in Botswana. Sixty five were returned and statistical analysis, using IBM SPSS V19 software, was used for analysis. Almost 85 per cent of respondents indicate that they are extremely or moderately aware of environmental design. Furthermore, the results indicate that 32 per cent of respondents have gone through formal training, which suggests ‘reasonable knowledge’. This however does not correspond with the use of the tools on the ground as 69 per cent of practitioners report never to have used any environmental building assessment tool in any project. The study highlights the need to develop an assessment tool for Botswana to enhance knowledge and further improve the level of awareness of environmental issues relating to building design and construction.

The growing dependence on electricity for economic growth in all countries prompts the need to manage current resources for future sustainability. In today’s world, greater emphasis is placed on energy conservation for energy security and for the development of every economy. However, for some countries understanding the basic drivers to such achievements is farfetched. The research presented in this paper investigates the electricity generation and access potential for Botswana. In addition detailed documentation and 13 years energy consumption and generation trends are investigated. Using questionnaires and empirical studies the energy demand for the entire nation was estimated. From the research it was established that current energy generation trends account for 38- 39% of the country’s population with access to electricity. Considering the percentage rate of sector energy demand, the proposed total installed capacity of 1332 MW, would not meet the country's energy demand at 100% access. The likely consequence of the lack of adequate supply would cumulate to significant increase of imports and/or load shedding to meet demand.

In order to reduce environmental impacts and achieve sustainability, it is important to balance the interactions \ud between the built and natural environment. The construction industry is becoming more aware of ecological concerns and the importance that biodiversity and maintenance ecosystem services has for sustainability. Bats constitute an important component of urban biodiversity and several species in the UK are highly dependent on buildings, making them particularly vulnerable to anthropogenic and environmental changes. Many buildings suitable for use as bat roosts often require re-roofing as they age and traditional bituminous roofing felts are frequently being replaced with breathable roofing membranes (BRMs). In the UK new building regulations and modern materials may substantially reduce the viability of existing roosts, yet at thesame time building regulations require that materials be fit for purpose. Reports suggest that both bats and BRMs may experience problems when the two interact. Such information makes it important to understand how house dwelling bats and BRMs may be affected. This paper considers the possible ways in which bats and BRMs may interact, how this could affect existing bat roosts within buildings and the implications for BRM service life predictions and warranties. \ud \ud Keywords –Breathable Roofing Membranes, Bats in Buildings, Material Deterioration, Sustainability, Conservation, Biodiversit

Botswana has a basic need to explore its energy concept, this being its energy sources, generation and percentage of the population with access to electricity. At present, Botswana generates electricity from coal, which supplies about 29% (on average) of the country’s demand. The other 71% is imported mainly from South Africa (Eskom). Consequently, the dependence of Botswana on imports posses threats to the security of its energy supply. As a result, there is the need to understand the bases for a possible generation expansion that would substantiate existing documentation. In view of this need, this study investigates the existing energy sources as well as energy consumption and production levels in Botswana. The study would be further developed by making projections of the energy demand up until the year 2020. The key techniques that were used include; literature review, questionnaire survey and an empirical study. The results presented indicated that, current dependable operation capacity (i.e. 100MW) should be increased to 2,595 MW or more assuming 85% plant efficiency. This would then be able to meet the growing demand for energy use. In addition, the installed capacity would be able to support commercial and mining activities for the growth of the economy.

Electricity consumption in Ghana is estimated to be increasing by 10% per annum due to the demand from the growing population. However, current sources of production (hydro and thermal facilities) generate only 66% of the current demand. Considering current trends, it is difficult to substantiate these basic facts, because of the lack of information. As a result, research into the existing sources of generating electricity, electricity consumption and prospective projects has been performed. This was achieved using three key techniques; review of literature, empirical studies and modelling. The results presented suggest that, current annual installed capacity of energy generation (i.e. 1960 MW) must be increased to 9,405.59 MW, assuming 85% plant availability. This is then capable to coop with the growing demand and it would give access to the entire population as well as support commercial and industrial activities for the growth of the economy. The prospect of performing this research is with the expectation to present an academic research agenda for further exploration into the subject area, without which the growth of the country would be stagnant.

Tracer gas techniques have been the most appropriate experimental method of determining airflows and ventilation rates in houses. However, current trends to reduce greenhouse gas effects have prompted the need for alternative techniques, such as passive sampling. In this research passive sampling techniques have been used to demonstrate the potential to fulfil these requirements by using solutions of volatile organic compounds (VOCs) and solid phase microextraction (SPME) fibres. These passive sampling techniques have been calibrated against tracer gas decay techniques and measurements from a standard orifice plate. Two constant sources of volatile organic compounds were diffused into two sections of a humidity chamber and sampled using SPME fibres. From a total of four SPME fibres (two in each section), reproducible results were obtained. Emission rates and air movement from one section to the other were predicted using developed algorithms. Comparison of the SPME fibre technique with that of the tracer gas technique and measurements from an orifice plate showed similar results with good precision and accuracy. With these fibres, infiltration rates can be measured over grab samples in a time weighted averaged period lasting from 10 minutes up to several days.\ud \ud Key words: passive samplers, solid phase microextraction fibre, tracer gas techniques, airflow, air infiltration, houses.

This paper assesses the potential for using building integrated photovoltaic (BIPV) \ud roof shingles made from triple-junction amorphous silicon (3a-Si) for electrification \ud and as a roofing material in tropical countries, such as Accra, Ghana. A model roof \ud was constructed using triple-junction amorphous (3a-Si) PV on one section and \ud conventional roofing tiles on the other. The performance of the PV module and tiles \ud were measured, over a range of ambient temperatures and solar irradiance. PVSyst (a \ud computer design software) was used to determine the most appropriate angle of tilt. It \ud was observed that 3a-Si performs well in conditions such as Accra, because it is \ud insensitive to high temperatures. Building integration gives security benefits, and \ud reduces construction costs and embodied energy, compared to freestanding PV \ud systems. Again, it serves as a means of protection from salt spray from the oceans and \ud works well even when shaded. However, compared to conventional roofing materials, \ud 3a-Si would increase the indoor temperature by 1-2 °C depending on the surface area \ud of the roof covered with the PV modules. The results presented in this research \ud enhance the understanding of varying factors involved in the selection of an \ud appropriate method of PV installation to offset the short falls of the conventional \ud roofing material in Ghana.

Ventilation often accounts for a significant portion of the heating or cooling load of a building and also affects the moisture levels of buildings. Arguably in the UK, houses with cold pitched roofs, with insulation on a horizontal ceiling, are the most vulnerable to the formation of condensation in the roof. This study is a numerical investigation of the occurrence and the risk of condensation formation in a cold pitched roof fitted with a vapour permeable underlay (VPU) as well as the energy benefits that would be obtained from reducing the ventilation gap in the eaves and improving the airtightness of the ceiling. In order to visualize these effects, several cases and scenarios have been modelled with a HAM software package. The results showed that the VPU is most effective at very low vapour resistances, Sd< 0.02. To a large extent, the proposed characteristic performance of the VPU as predicted by manufacturers and some researchers may only be realistic if gaps in the ceiling are sealed off completely when houses are being built, which may be practically difficult given current construction practice. Substantial energy gains were predicted when the roof was completely sealed off. Ideally, reducing the overall tightness of the building envelope to smaller air change rates (< 5 ach at 50 Pa), would reduce the airflow through the ceiling, and would help in controlling condensation formation in the roof as well as reduce the energy loss through the roof and hence of the building. Keywords: Vapour permeable underlay, airtightness, condensation, cold pitched roofs

In this paper, the effect of the Building Integrated Photovoltaic (BIPV) system on the building energy demand from the grid is investigated. The main load of the building is due to the Heating, Ventilation and Air-Conditioning (HVAC) equipment, and its load is highly correlated with the ambient temperature. Similarly, the BIPV system output is also dependent on the ambient conditions, and increases with higher solar irradiation but tends to reduce as temperatures decrease when all other factors are constant. BIPV systems, thus, have the potential to help building owners and operators, both from energy production and load reduction/shifting aspects. In this paper, we utilize a 12-month operational data from the BIPV system at Yasar University, and assess its performance from energy generation and demand reduction perspectives.

FOREWORD: I would like to welcome each participant to the WABER 2021 Conference. Since its inception in 2009, the WABER Conference series has done a great deal to nurture and support researchers, initially in West Africa, also, in other parts of Africa and elsewhere. I would like to thank all delegates for your participation which enables us to keep this Conference going. The WABER Conference enjoys a positive international reputation and has continued to grow from strength to strength over the past 13 years. For this, I would like to thank our team, keynote speakers and participants over the years for every contribution you have made to the success of this Conference. This year's Conference has an excellent programme, line up of speakers and authors.\ud I would like to thank and commend the authors of all 72 papers in this Conference proceedings. If the research paper writing process was compared to a marathon, the authors of the 72 papers in this publication would be adjudged as the ones who have endured and finished the race. We opened the call for papers for this Conference in December 2020 and over 100 abstracts were submitted by authors. However, it is one thing to propose to write a paper, and it is quite another thing to actually write the paper. Therefore, I would like to thank and congratulate all authors who succeeded in completing the process of getting published in this conference proceedings. It is befitting that we have an excellent range of interesting topics in the 72 papers to be discussed at this conference. We are honoured to welcome Professor Charles Egbu, Vice Chancellor of Leeds Trinity University, to give us a special opening address. In the three days of this conference, we will have various plenary presentations by experienced international academics and I would like to thank and welcome each of them below. Professor Albert Chan Richard Lorch Professor Taibat Lawanson Professor Dato’ Sri Ar Dr Asiah Abdul Rahim Professor George Ofori.\ud In addition to these speakers, we have other interesting sessions on the programme including a special session for doctoral students and supervisors several other experienced speakers addressing various topics that should be of interest to many of us.\ud I would like to thank all members of the organising team particularly Associate Professor Emmanuel Essah, Dr Yakubu Aminu Dodo and Dr Sam Moveh for their efforts which has helped to organise this Conference successfully. I would also like to thank all of our reviewers particularly Associate Professor Emmanuel Essah and Dr Haruna Moda for the considerable time and effort spent reviewing and checking all papers to ensure a high standard of quality.\ud The WABER Conference Team always plays an excellent role in the success of our events and I would like to thank and appreciate the contributions of Florence, Sam Boakye, Victor Ayitey and his team, Kwesi Kwofie and Issah Abdul Rahman to the success of this Conference.\ud I hope you enjoy our first hybrid conference and engage with our exciting speakers on the diverse topics that will be covered over the three days of this Conference.