The Experts below are selected from a list of 31698 Experts worldwide ranked by ideXlab platform
Robert Irving - One of the best experts on this subject based on the ideXlab platform.
-
development and application of a domestic heat pump model for estimating co2 emissions reductions from domestic space Heating Hot Water and potential cooling demand in the future
Energy and Buildings, 2013Co-Authors: Rajat Gupta, Robert IrvingAbstract:Abstract This paper outlines the development and application of a domestic heat pump model for space Heating and cooling energy. The model is intended to bridge the gap between the single coefficient of performance parameter currently used in the UK procedures for the assessment of the energy efficiency of dwellings and the dynamic simulation models frequently developed for the academic estimation of heat pump energy use. It is responsive to variations in source and sink temperatures whilst being simple enough to be embedded in a spreadsheet model. The model was developed by: building a regression model, using heat pump performance test results, relating heat pump coefficient of performance to the differential between source and sink temperatures – “lift”; deriving estimating rules for monthly supply temperature estimates for commonly-used heat pump sources and for demand temperatures for normal wet central Heating sinks to give a monthly estimate for the source/sink differential; embedding the regression model in the UK standard model for domestic energy estimation, with additional routines to estimate energy consumption for additional heat and for space cooling. The model developed was validated by comparison with the existing BREDEM model. Compared with the standard BREDEM estimates, the resulting model showed correct response to changes in ambient temperatures, allowing correct estimating of consumption for additional heat under conditions of climate change. It showed variation of heat pump coefficient of performance across the year, allowing better estimation of winter peak load.
Maidme G. - One of the best experts on this subject based on the ideXlab platform.
-
Preliminary Study of a Solar Assisted Heating System
2020Co-Authors: Davies G., Lowe J., Hall R., Maidme G.Abstract:Urgent measures are needed to combat worldwide climate change, including the development of efficient, cost-effective, low carbon, renewable heat sources. The current paper investigates a novel, low cost, solar thermal energy based system, namely a low-emissivity transpired solar collector. This consists of a metal, solar collector plate with a spectrally sensitive surface, and a large number of holes drilled into it, through which ambient air is drawn, into a plenum. The plenum air is then heated by convection from the collector plate, typically increasing its temperature by 15-20 K (27-36°R). The heated air is continually extracted from the plenum and can be used, for example, for space Heating or for pre-Heating Hot Water for buildings. This can be achieved either directly by using the solar heated air in ventilation Heating systems, or heat exchangers can be used to transfer the heat generated by the solar collector to other air or Water circulation systems, thereby combining the solar heat with that from gas, electric heaters or heat pumps. The novel solar heated collector considered in the present study could be used in the form of cladding attached to a vertical building wall. Advantages are that it is: (i) thermally efficient, achieving a significant increase in temperature from a relatively small area, even in winter; (ii) a low/zero carbon renewable Heating source; (iii) low cost (in terms of both capital and operating costs), requiring only a low powered fan to force air through the solar collector plate; (iv) readily combined with other Heating systems, such as heat pumps. The current paper investigates the use of the solar collector integrated with other Heating systems in a number of configurations, enabling it to meet the Heating demand for a range of building types. Its effectiveness in the different configurations was evaluated and compared using models to investigate the various heat transfer steps involved and estimate the heat delivered by each system for a range of applications. In each case, the energy, carbon and cost savings achieved when using the solar collector are compared to those for a conventional (fossil fuel based) Heating system. The results from these analyses together with recommendations for further development and future use of the solar collector integrated with other Heating systems are reported. This paper was published in ASHRAE Winter Conference 2010. Copyright 2010 ASHRAE, Inc. Reprinted by permission at . This article may not be copied and/or distributed electronically or in paper form without permission of ASHRAE. For more information about ASHRAE Winter Conference 2010, visit www.ashrae.or
-
Investigation of a Solar Assisted Heating System
2020Co-Authors: Davies G., Lowe J., Hall R., Maidme G.Abstract: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
Biplab Das - One of the best experts on this subject based on the ideXlab platform.
-
effect of the absorber surface roughness on the performance of a solar air collector an experimental investigation
Renewable Energy, 2020Co-Authors: Biplab Das, Jayanta Deb Mondol, Suman Debnath, Adrian Pugsley, Mervyn Smyth, Aggelos ZacharopoulosAbstract:Abstract Solar air collectors (SAC) convert the available solar energy into useful thermal energy for different Heating applications such as drying, space Heating, Hot Water etc. The study aims to enhance the thermal performance of a flat plate SAC by modifying the absorber surface. The experimental performance of two variant SACs (a sand coated absorber to increase surface roughness and a conventional plain absorber) was compared under controlled laboratory conditions The experimental tests were performed under a solar simulator for radiation levels of 400, 600, and 800 W/m2 and variable air mass flow rate ranging from 0.01 to 0.02 kg/s/m2. Results indicated that increasing the air flow rate by 90% enhanced the thermal efficiency on a plain absorber SAC by almost 68%, and the rate of increase was higher for the sand coated absorber. SAC with the sand coated absorber provided additional surface area resulting in an increase in the effective heat transfer. The thermal efficiency of the collector was improved by up to 17% for the sand coated absorber compared to the plain absorber. The absolute thermal efficiency of the SAC varied from 19% to 41% under the different tests conditions.
Hao Liu - One of the best experts on this subject based on the ideXlab platform.
-
a review of the applications of phase change materials in cooling Heating and power generation in different temperature ranges
Applied Energy, 2018Co-Authors: John Kaiser Calautit, Zhonghua Wang, Hao LiuAbstract:Latent heat thermal energy storage is an attractive technique as it can provide higher energy storage density than conventional heat energy storage systems and has the capability to store heat of fusion at a constant (or a near constant) temperature corresponding to the phase transition temperature of the phase change material (PCM). This paper provides a state-of-the-art review on phase change materials (PCMs) and their applications for Heating, cooling and electricity generation according to their working temperature ranges from (−20 °C to +200 °C). Four working temperature ranges are considered in this review: (1) the low temperature range from (−20 °C to +5 °C) where the PCMs are typically used for domestic and commercial refrigeration; (2) the medium low temperature range from (+5 °C to +40 °C) where the PCMs are typically applied for Heating and cooling applications in buildings; (3) the medium temperature range for solar based Heating, Hot Water and electronic applications from (+40 °C to +80 °C); and (4) the high temperature range from (+80 °C to +200 °C) for absorption cooling, waste heat recovery and electricity generation. Different types of phase change materials applied to each temperature range are reviewed and discussed, in terms of the performance, heat transfer enhancement technique, environmental impact and economic analysis. The review shows that, energy saving of up to 12% can be achieved and a reduction of cooling load of up to 80% can be obtained by PCMs in the low to medium–low temperature range. PCM storage for Heating applications can improve operation efficiency from 26% to 66%, depending on specific applications. Solar thermal direct steam generation (DSG) is the most common electricity generation application coupled with PCM storage systems in the high temperature range, due to the capability of PCMs to store and deliver energy at a given constant temperature. The recommendations for future research are also presented which provide insights about where the current research is heading and highlights the challenges that remain to be resolved.
Rajat Gupta - One of the best experts on this subject based on the ideXlab platform.
-
development and application of a domestic heat pump model for estimating co2 emissions reductions from domestic space Heating Hot Water and potential cooling demand in the future
Energy and Buildings, 2013Co-Authors: Rajat Gupta, Robert IrvingAbstract:Abstract This paper outlines the development and application of a domestic heat pump model for space Heating and cooling energy. The model is intended to bridge the gap between the single coefficient of performance parameter currently used in the UK procedures for the assessment of the energy efficiency of dwellings and the dynamic simulation models frequently developed for the academic estimation of heat pump energy use. It is responsive to variations in source and sink temperatures whilst being simple enough to be embedded in a spreadsheet model. The model was developed by: building a regression model, using heat pump performance test results, relating heat pump coefficient of performance to the differential between source and sink temperatures – “lift”; deriving estimating rules for monthly supply temperature estimates for commonly-used heat pump sources and for demand temperatures for normal wet central Heating sinks to give a monthly estimate for the source/sink differential; embedding the regression model in the UK standard model for domestic energy estimation, with additional routines to estimate energy consumption for additional heat and for space cooling. The model developed was validated by comparison with the existing BREDEM model. Compared with the standard BREDEM estimates, the resulting model showed correct response to changes in ambient temperatures, allowing correct estimating of consumption for additional heat under conditions of climate change. It showed variation of heat pump coefficient of performance across the year, allowing better estimation of winter peak load.