789 research outputs found

    Project SHOES: Secondary heat opportunities from electrical substations

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    Through the mechanism of stepping up and stepping down voltages with electrical power transformers, losses in the form of heat occur and are dissipated to the atmosphere. These losses have the opportunity to be recovered and upgraded to help support the thermal demands of buildings as allow carbon secondary heat source. The electrification of heat facilitates the uptake of electrically driven heat pumps that are efficient means of upgrading low temperature heat sources to commonly used temperatures and the employment of district heating networks enables the transition of these alternative heat sources into the economy. This paper describes the results discovered from an initial investigation on the contribution available from a transformer energy recovery scheme using the Southampton Bulk Supply Point substation and District Heating Scheme as a case study. Benefits to the heat sector and asset owner are analysed from the results considering the techno-economic, environmental and social performance with the aim to provide guidance to the engineering community for further in-depth feasibility studies on this waste energy recovery concep

    Investigation of a Solar Assisted Heating System

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    Low emissivity transpired solar collectors (low-ε TSCs) consist of metal solar absorber, collector plates, with a spectrally sensitive surface, perforated with holes. Ambient air is drawn through the holes and heated by convection from the solar collector plate, increasing the air temperature by up to 25 K. The heated air can be used for e.g. space heating or pre-heating hot water, in buildings. The performance of low-ε TSCs combined with heat pumps in various configurations, to deliver heat to buildings, has been investigated using computational models and compared with conventional heating systems to determine the potential energy, carbon and cost savings available. The results showed that using low-ε TSCs incorporated into a heat pump based ventilation air system produced annual savings in energy, CO2e and costs of up to 14%, compared to similar systems where the TSC was not used. The greatest savings were achieved when using an exhaust air heat pump. Recommendations for further development of this novel technology are also presented

    Causes, Consequences and Prevention of Refrigeration Fires in Residential Dwellings

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    There are around 300 residential dwelling fires in Great Britain each year where a fridge or freezer is cited as the cause. A number of these incidents have resulted in injuries/fatalities and produced significant levels of property damage. This paper examines the causes and consequences of refrigeration fires in residential dwelling fires in Great Britain (London and England) and the evidence collected via fire investigation of residential dwelling fires involving fridges or freezers. Analysis of the data collected from these fires suggests that, once ignition occurs, fires started by faults in fridge/freezers are more likely to spread beyond both the appliance and the room of origin, and tend to cause more damage than fires started by the other types of white goods appliance (washing machine, dishwasher or tumble dryer). A number of common failure modes leading to ignition in domestic refrigeration fires, along with specific fire escalation and spread mechanism are identified. Based upon the information obtained from fire investigations and a comparison between the design and construction of refrigeration appliances used in Great Britain and USA, a number of recommendations are suggested which could be used to help reduce the risk of domestic refrigeration fires

    Study of novel solar assisted heating system

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    The potential for energy, carbon dioxide equivalent (CO2e) and cost savings when using low emissivity (low-ε) transpired solar collectors (TSCs), combined with heat pumps in a range of configurations, has been investigated using computer modelling. Low-ε TSCs consist of metal solar collector plates with a spectrally sensitive surface, perforated with holes. Ambient air is drawn through the holes and heated by convection from the solar collector plate, increasing the air temperature by up to 25 K. The heated air can be used for e.g. space heating, or pre-heating water in buildings. The models developed have been used to compare the performance of low-ε TSC/heat pump heating systems in small and large buildings, at a range of locations. The model results showed savings in energy, CO2e and costs of up to 16.4% when using low-ε TSCs combined with an exhaust air heat pump compared with using the exhaust air heat pump alone. Practical application: If the UK is to meet its target of reaching net zero greenhouse gas emissions by 2050, it will be necessary to adopt low or zero carbon heating technologies. The novel low emissivity transpired solar collector device investigated can contribute to this. Its advantages include: (i) utilising solar radiation; (ii) readily integrated with existing heating systems e.g. heat pumps; (iii) significant energy, CO2e emissions and cost savings; (iv) low cost device; (v) minimal energy input i.e. one small fan; (vi) can be retrofitted to existing buildings; (vii) its benefits were applicable at all of the (wide range of) locations tested

    Relationship between specific energy consumption and size of supermarket stores

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    © 2019 International Institute of Refrigeration. All rights reserved. Energy consumption data for 2017 were analysed for 190 retail (supermarket) stores from one retailer in the UK. The relationship between energy consumption and store size was investigated. The mean energy intensity defined by the ratio of electrical energy consumption across the sales floor area was 866 kWh.m-2.yr-1 for an average sales floor area of 469 m2. Plotting energy intensity against store size showed that smaller stores had a higher energy intensity. Measuring energy intensity using electrical energy consumption, total energy consumption, sales or gross floor area, perimeter area of the store and store volume all showed a similar trend. Electrical energy consumption is well correlated with refrigeration capacity (r2 = 0.779), however, it is has a slightly better correlation with sales floor area (r2 = 0.883). . When including these data with other data from previous studies, it can be seen that large stores (supermarkets) had an approximately constant energy intensity (decreasing slightly with increased floor area) and smaller stores (convenience) had a much higher energy intensity which increases strongly with decreasing floor area. Therefore to represent stores ranging from small to large a power law relationship is required

    Enabling knowledge brokerage intermediaries to be evidence-informed

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    TARGET AUDIENCE: What Works Centres; other intermediary brokerage agencies; their funders and users; and researchers of research use. BACKGROUND: Knowledge brokerage and knowledge mobilisation (KM) are generic terms used to describe activities to enable the use of research evidence to inform policy, practice and individual decision making. Knowledge brokerage intermediary (KBI) initiatives facilitate such use of research evidence. This debate paper argues that although the work of KBIs is to enable evidence-informed decision making (EIDM), they may not always be overt and consistent in how they follow the principles of EIDM in their own practice. KEY POINTS FOR DISCUSSION: Drawing on examples from existing brokerage initiatives, four areas are suggested where KBIs could be more evidence-informed in their work: (1) needs analysis: evidence-informed in their analysis of where and how the KBI can best contribute to the existing evidence ecosystem; (2) methods and theories of change: evidence-informed in the methods that the KBI uses to achieve its goals; (3) evidence standards: credible standards for making evidence claims; and (4) evaluation and monitoring: evidence-informed evaluation of their own activities and contribution to the knowledge base on evidence use. For each of these areas, questions are suggested for considering the extent that the principles are being followed in practice. CONCLUSIONS AND IMPLICATIONS: KBIs work with evidence but they may not always be evidence-informed in their practice. KBIs could benefit from more overtly attending to the extent that they apply the logic of EIDM to how they work. In doing so, KBIs can advance both the study, and practice, of using research evidence to inform decision making

    Application of Phase Change Materials to Domestic Refrigerators

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    The paper investigates the performance improvement provided by a phase change material associated with the evaporator in a domestic refrigerator. The heat release and storage rate of encapsulated ice, used as the thermal energy storage material, has been investigated numerically. The mathematical model for phase change is based on the enthalpy method and the governing equations were discretized on a fixed grid using the finite difference method. The influence of PCM thickness (2, 3 and 4 × 10-3 m slabs), ambient temperature (20°C, 25°C, 30°C and 43°C) and evaporating temperature (-15°C and -10°C) have been investigated. The results showed that the melting and freezing time increased proportionally with PCM thickness. The refrigerator autonomy was reduced by 47% when the ambient temperature was increased from 20°C to 43°C and the freezing time increased by 27% when the evaporating temperature was reduced from -10°C to -15°C. Overall, the model provides a useful tool for evaluating the design and operation of a thermal storage refrigerator
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