Browsing by Author "Wright, A. J."

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    Airconditioning surveys in the UK retail sector, or Keeping the Cold in.
    (2006) Brown, Neil; Caiero, J.; Wright, A. J.; Bruhns, H.; Summerfield, A.; Oreszczyn, T.
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    Appliances taxonomy across both domestic and non-domestic building sectors.
    (2008) Marjanovic-Halburd, Ljiljana; Coleman, Michael; Bruhns, H.; Summerfield, A.; Wright, A. J.
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    Application of the superposition technique in conduction heat transfer for analysing arrays of shallow boreholes in ground source heat pump systems
    (University of Nottingham, 2019-09-08) Naranjo-Mendoza, Carlos; Wright, A. J.; Oyinlola, M. A.; Greenough, R. M.
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    Are shallow boreholes a suitable option for inter-seasonal ground heat storage for the small housing sector?
    (Oklahoma State University, 2018-09) Naranjo-Mendoza, C.; Wright, A. J.; Greenough, R. M.
    In recent years, various researchers have studied the performance of Solar Assisted Ground Source Heat Pump (SAGSHP) systems using borehole heat exchangers. However, the research conducted has been limited to conventional boreholes (30m to 150m depth), which are expensive and not suitable for the small housing sector. This paper reports an experimental analysis of a shallow SAGSHP system with inter-seasonal storage. The system, installed in Leicester UK, consists of seven photovoltaic-thermal (PVT) collectors connected in series with an array of 16 shallow boreholes (1.5 meters depth). Data regarding the energy fluxes involved in the soil-based thermal store have been monitored and analysed for one year. The results show that the shallow soil is able to serve as a storage medium to cover the heating demands of a near zero energy domestic building. However, it was noticed that in addition to the solar heat captured and stored in the soil, the system covers part of the heating demand from heat extracted from the soil surrounding the thermal store. During winter, the lowest temperature reached by the soil so far is 2 °C. Hence, no freezing problems have occurred in the soil. An analysis of the temperature variation of the ground storage under the system operation is also shown.
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    Assessing the efficacy of passive measures for the tropical context of Mauritius through parametric simulations and in-situ measurement
    (Chartered Institution of Building Services Engineering, 2021-07-13) GOOROOCHURN, MAHENDRA; Coret, Jonathan Yannick; Brown, Neil; Santaram, Venkannah; Wright, A. J.
    The transition from the traditional creole typology to the modern concrete vernacular structures has taken place progressively over the past few decades in Mauritius, motivated by the need for cyclone resistant buildings. However, the lack of consideration for thermal properties of the wall, glazing and roof construction has resulted in interior space conditions generally uncomfortable during summer conditions, evidenced by the increasing installation and use of air conditioning systems. With summers projected to become warmer due to climate change, passive design measures should be re-incorporated into existing and new constructions to decouple active cooling and urbanisation. This paper describes the parametric analyses carried out to generate cooling load (peak and coincident) for wall, glazing and roof components and temperature (operative, radiative and air) variations for a test building model made up of nine rooms, of which eight were peripheral and one central (with no external walls). The simulations were undertaken in Designbuilder® for a base case with no passive measures and for various low cost passive measures – overhang of various depths, external vertical shading and curtains, roof shading and planting tall trees around the building, incrementally rotated. The results allowed to assess the efficacy of each passive measure, validated against experimental data collected in actual buildings. The study also provided much needed quantitative data on surface and air temperatures prevailing inside buildings, which are key to bringing about the needed shift in mindset and the construction market.
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    Benchmarking acute hospitals: Composite electricity targets based on departmental consumption intensities?
    (Elsevier, 2016-03-04) Morgenstern, Paula; Li, Maria; Raslan, Rokia; Ruyssevelt, PAul; Wright, A. J.
    This study aims to explore how meaningful energy benchmarks—reflecting good energy management and design—can be constructed for hospital buildings, a category encompassing complex buildings with different set-ups and large variability between them. Current energy targets are sometimes considered of limited use by facility professionals in health care because they do not take account of differences in service delivery between acute hospitals which result in differing use of medical equipment and requirements for room conditioning. For this study, the electricity use of a number of department types has been quantified using on-site measurements. Findings confirm that different hospital departments have hugely varied electricity consumption characteristics. Wards, day clinics and some other departments have lower average consumption intensities which are reasonably well reflected by current hospital electricity benchmarks. Theatres, laboratories and also departments such as imaging and radiotherapy showed much higher consumption intensities exceeding available targets. A revision of current energy benchmarks for the latter category is therefore strongly recommended. It is further proposed to develop composite benchmarks for hospitals taking into account differing energy intensities at a departmental level for guidance and as basis for certification.
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    Case study investigation of overheating in low-energy homes: insights from a post-occupancy evaluation in England
    (Taylor and Francis, 2024-12-16) Toledo, Linda; Wright, A. J.; Cropper, Paul
    This paper presents evidence of overheating in present-day low-energy homes and explores the causes of this phenomenon. The study involved in-depth research on four low-energy homes in England. Three of these were newly built, while the other was retrofitted. Over a period of 11 months, the homes underwent environmental monitoring, and user perspectives were gathered. Additionally, a retrospective analysis was conducted based on the Building Regulations 2010 Overheating: Approved Document O. Overheating was primarily attributed to design factors related to ventilation (linked to both mechanical ventilation and natural ventilation), solar control (inadequate G-values), and the unique architectural elements (roof pod and sunspace). While most occupants employed adaptive behaviours whenever possible to cope with the high indoor temperatures, these strategies proved insufficient in preventing overheating in three out of four cases. The study also compared different methods for assessing overheating in low-energy homes. CIBSE-TM59 was found to be effective in identifying overheating issues and aligning with occupant perceptions. England Building Regulations Part O simplified method failed to account for potential overheating from deep energy retrofits, as well as possible exacerbations from roof pods and from transition spaces. Moreover, all assessments failed to encompass the elevated risk for (permanent or transitory) vulnerable occupants.
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    Central heating thermostat settings and timing: building demographics
    (2009) Shipworth, M.; Firth, Steven; Gentry, M. I.; Wright, A. J.; Shipworth, D. T.; Lomas, K. J.
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    A comparison of analytical and numerical model predictions of shallow soil temperature variation with experimental measurements
    (Elsevier, 2018-06-28) Naranjo-Mendoza, C.; Wright, A. J.; Oyinlola, M. A.; Greenough, R. M.
    In several fields of enquiry such as geothermal energy, geology and agriculture, it is of interest to study the thermal behaviour of shallow soils. For this, several analytical and numerical methodologies have been proposed to analyse the temperature variation of the soil in the short and long term. In this paper, a comparative study of different models (sinusoidal, semi-infinite and finite difference method) is conducted to estimate the shallow soil temperature variation in the short and long term. The models were compared with hourly experimental measured data of soil temperature in Leicester, UK, at depths between 0.75 and 2.75 m. The results show that the sinusoidal model is not appropriate to evaluate the short-term temperature variations, such as hourly or daily fluctuations. Likewise, this model is highly affected by the undisturbed ground temperature and can lead to very high errors. Regarding the semi-infinite model, it is accurate enough to predict the short-term temperature variation. However, it is useless to predict the long-term variation at depths greater than 1 m. The finite difference method (FDM) considering the air temperature as a boundary condition for the soil surface is the most accurate approach for estimating both short and long-term temperature variations while the FDM with heat flux as boundary condition is the least accurate approach due to the uncertainty of the assumed parameters. The ranges of errors for the sinusoidal, semi-infinite and FDM are found to be from 76.09 to 142.13%, 12.11 to 104.88% and 1.82 to 28.14% respectively.
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    Concepts for dynamic modelling of energy-related flows in manufacturing
    (Elsevier, 2013) Wright, A. J.; Oates, M. R.; Greenough, R. M.
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    Design of a thermal store and heat pump system with hybrid photovoltaic-thermal solar charging for a low energy house in England
    (Bulgarian Academy of Sciences, 2024-05-14) Wright, A. J.; Khattak, Sanober
    Low carbon domestic heating is a major challenge for cold climates such as the UK, where most homes still use fossil gas boilers. Heat pumps have lower carbon emissions. Use of ground or water instead of air as a heat source allows the option of thermal storage from solar or other sources and can improve the efficiency of the system. This paper considers the options for a large, detached house to be built in south-west England, including comparison of a ground and water storage, use of photovoltaic-thermal panels for heat and electricity, design of the house to minimise heat loss, and timescales of thermal storage.
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    Design of Sustainable Industrial Systems by Integrated Modelling of Factory Building and Manufacturing Processes
    (2012) Oates, M. R.; Despeisse, M.; Ball, P. D.; Evans, S.; Greenough, R. M.; Hope, S. B.; Levers, A.; Lunt, P.; Quincey, R.; Shao, L.; Waltniel, T.; Wheatley, C.; Wright, A. J.
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    Dwelling temperatures and comfort during the August 2003 heatwave
    (Sage, 2005-01-01) Wright, A. J.; Natarajan, S.; Young, A. N.
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    Effects of Future Climate Change and Adaptation Measures on Summer Comfort of Modern Homes across the Regions of the UK
    (MDPI, 2022-01-12) Wright, A. J.; Venskunas, Eduardas
    The global climate is warming rapidly, with increasing frequency of severe events including heatwaves. Building insulation standards are improving to reduce emissions, but this can also lead to more overheating. Historically, UK house designers have not included adaptation measures to limit this. Most studies of the problem have had limited geographical or future cli-mate scope. This study considers the comfort performance of a small modern house, in detached, semi-detached, and terrace (row) forms, but otherwise identical. Overheating is evaluated ac-cording to established criteria, including night-time bedroom hours over 26°C. Simulations are carried out using median future weather years for current, 2030s, 2050s, and 2080s climates un-der medium- and high-emission scenarios for 14 regions of the UK. The results show a very large increase in overheating by the 2080s in all regions. With solar shading and natural ventilation, overheating is reduced considerably, maintaining comfort in most northern regions in the 2050s and a few northern regions in the 2080s. Differences between medium and high emissions are generally less than between different decades. Terraced (row) houses consistently overheat slightly more than semi-detached, with detached showing the least overheating.
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    Energy and economic evaluation of a solar assisted ground source heat pump system for a north Mediterranean city
    (Elsevier, 2020-11-27) Wright, A. J.; Sakellariou, Evangelos; Axaopoulos, Petros
    In this study, a PVT based solar assisted ground source heat pump (SAGSHP) system was investigated regarding its energy performance and cost-effectiveness for the city of Thessaloniki (Greece). The SAGSHP system was set up to cover the space heating and domestic hot water needs for a low-rise dwelling. A mathematic model of the system was formulated in TRNSYS was used with the aim to carry out parametric analysis by varying the number of the PVTs. Two of the most important components of the employed model, the PVT collector and the geothermal heat exchanger, have already been validated via experimental data. Simulations were conducted and through the results seven energy metrics were estimated, with the objective to examine the system’s energy performance from various perspectives. The SAGSHP system with 16 PVTs was found capable of covering 73 % of the heating load and to generate 1.22 times more electricity than that consumed by the system. The electricity yield of PVTs was not affected throughout the parametric analysis, and the maximum specific productivity was estimated at 301.5 kWhe PVT-1 per year. The results suggest that a SAGSHP system equipped with about 14 PVTs can reach energy self-sufficiency. As regards the economics of the SAGSHP system, this was compared with a natural gas boiler system via two methods: life cycle cost (LCC) and life cycle savings (LCS). A sensitivity analysis with major economic parameters of the systems was carried out. It was found that the cost-effectiveness of the SAGSHP system is influenced mainly by its capital cost and by the price of the natural gas. Systems equipped with less than 12 PVTs can be cost-competitive by subsiding from 8 % up to 42 % of their capital cost. Also, system with more than 12 collectors were found of more benefit than the smaller ones, in the case where feed-in-tariff schemes are applied, or the bank loan’s interest rate is low. It can be concluded that, the proposed system can be an attractive monetary solution for covering the heating load in comparable dwellings with a similar climate to Thessaloniki.
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    Energy flow management of a hybrid renewable energy system with hydrogen.
    (IEEE, 2010) Baumann, Lars; Boggasch, E.; Rylatt, R. M.; Wright, A. J.
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    Energy, economic and emission assessment of a solar assisted shallow earth borehole field heat pump system for domestic space heating in a north European climate
    (Elsevier, 2021-06-15) Wright, A. J.; Sakellariou, Evangelos; Axaopoulos, Petros
    The performance of a solar assisted ground source heat pump (SAGSHP) system was evaluated and compared with a conventional gas boiler system using simulation, for a central England location. The earth energy bank was the long-term heat store element of the system and consisted of a very shallow field (1.5 m deep) of borehole heat exchangers (BHE). The mathematical model of the system was formulated, and parametric analyses were carried out by varying the number of BHEs and their spacing. The energy performance was expressed using four energy metrics, while its economy and CO2e emissions were compared with a natural gas boiler (NGB) system via the life cycle cost method and the fractional CO2e savings, respectively. The system can be energy self-sufficient by installing 40 BHEs at 1.25 m spacing or with 32 BHEs at 1.5 m spacing. The NGB system appears more economic than the SAGSHP system, due to low natural gas prices, the high price of the imported electricity, the low price of the exported electricity and the higher capital cost of the SAGSHP system. However, the SAGSHP system was found to have net negative carbon emissions, in contrast to the high positive emissions of the NGB system.
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    Evaluation of the viability of solar PV for Kurdistan
    (World Energy and Environment Technology Ltd, 2018-01-25) Wright, A. J.; Bulbas, Tavgar
    Iraqi Kurdistan, or officially the Kurdistan Region, is an autonomous region of Iraq. Following the Iraq war of 2003, it became relatively stable and prosperous, at least compared to the rest of Iraq which was very unstable. More recently the Kurdistan Region has played a major role in the war against ISIS, and receiving large numbers of refugees and displaced persons from surrounding conflict zones, particularly Syria. These factors have led to a rapid increase in energy demand. The region has gas and oil, and also generates hydro power. Most of the country is on the electricity grid, but supply is often unable to meet demand causing frequent power cuts and rationing. Some of the shortfall is made up by private generators connected locally to the grid. Solar photovoltaic (PV) power has seen rapid growth globally in recent years due mainly to falling prices of panels, and proven performance. In the Kurdistan Region PV has very low penetration, but great potential given high levels of solar radiation. However, within the Kurdistan Region there is great variation in the viability of PV power due to differences in climate, political stability, and proximity to conflict. This paper, using novel data gathering methods because conventional approaches are impractical, assesses the potential for PV in 31 locations according to seven criteria, and gives an overall score from 0 to 10. Eight scored 8-10; fourteen scored 6-7. The results show a wide variation in suitability of PV. A similar approach could be applied to analyze viability in other regions with similar issues. The technical options for PV connection are considered, including cost and potential for islanding, together with other renewable energy options.