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Articles 1 - 12 of 12
Full-Text Articles in Mechanical Engineering
Addressing Low Heat Pump Heating System Sales In The Uk, Ben Costelloe
Addressing Low Heat Pump Heating System Sales In The Uk, Ben Costelloe
Articles
The replacement of existing fossil fuel boilers with heat pumps is seen as a key measure in the decarbonisation of heating systems and addressing climate change. This policy however, is currently failing in many Western European states, particularly in the UK. The many reasons for this situation are examined. However, the age of UK housing stock and particularly the high number of dwellings built prior to the introduction of building insulation regulations in 1980, are key. To maintain the running cost of air source heat pumps competitive with those of the gas boilers they generally replace the heat pump lift …
Building Performance - Societal Drive, Programme And Symposium, Joseph Little, Patrick Daly
Building Performance - Societal Drive, Programme And Symposium, Joseph Little, Patrick Daly
Articles
Society is increasingly looking at the construction industry to mitigate the environmental crisis and solve the housing crisis through wholesale embrace of three broad sets of challenges. The MSc in Building Performance (Energy Efficiency in Design) (MSc BP(EED)) was created in 2017 to provide significant upskilling in the knowledge, skills, and software applications of building design professionals so that they can meet these challenges, while creating compliant, sustainable, super-low energy, new and renovated buildings. The delivery of the programme supports upskilling of employed building design professionals at Masters level, encouraging a minority to develop their capacity and interest in research …
The Application Of Evolutionary Algorithms In Multi-Objective Design And Optimization Of Air Cooled Heatsinks, Younis Osama Abdelsalam, Sajad Alimohammadi, Tim Persoons
The Application Of Evolutionary Algorithms In Multi-Objective Design And Optimization Of Air Cooled Heatsinks, Younis Osama Abdelsalam, Sajad Alimohammadi, Tim Persoons
Articles
Genetic algorithms (GAs) are considered to be one of the main types of evolutionary algorithms (EAs) and are being increasingly used in various engineering design applications. To a large extent, plate-fin heatsinks are used in the thermal management of compact electronic equipment and data centers. The shape optimization of the heatsinks is not rigorously investigated during the design process of high power electronics. Any improvements in the effectiveness of the heatsinks impact the energy consumed by large-scale information communication technology (ICT) facilities including data centers and telecommunication systems and promote a more sustainable use of raw materials. This paper investigates …
A Techno-Economic Analysis Of Current Cooling Techniques In Irish Data Centres, Lee Gibbons, Bryan Coyne, David Kennedy, Sajad Alimohammadi
A Techno-Economic Analysis Of Current Cooling Techniques In Irish Data Centres, Lee Gibbons, Bryan Coyne, David Kennedy, Sajad Alimohammadi
Articles
This research is part of a comprehensive study to determine reformative actions for cooling regimes within the Irish data centre market. To achieve this goal, preliminary Exergy, Entropy change and operational cost analyses are used. It is determined that there is no clear advantage for using one cooling method over another without knowing the data centres secondary function (e.g. district heating, energy generation). Air cooling technology is a good candidate for a highly reliable system due to the low exhaust temperatures of 30°C. Two-phase immersion is a possibility for economically viable data centres where operational costs are to be minimised, …
Economic, Energy And Ghg Emissions Performance Evaluation Of A Whispergen Mk Iv Stirling Engine Μ-Chp Unit In A Domestic Dwelling, Gerry Conroy, Aidan Duffy, Lacour Ayompe
Economic, Energy And Ghg Emissions Performance Evaluation Of A Whispergen Mk Iv Stirling Engine Μ-Chp Unit In A Domestic Dwelling, Gerry Conroy, Aidan Duffy, Lacour Ayompe
Articles
This paper presents an assessment of the energy, economic and greenhouse gas emissions performances of a WhisperGen Mk IV Stirling engine μ-CHP unit for use in a conventional house in the Republic of Ireland. The energy performance data used in this study was obtained from a field trial carried out in Belfast, Northern Ireland during the period June 2004 - July 2005 by Northern Ireland Electricity and Phoenix Gas working in collaboration with Whispertech UK. A comparative performance analysis between the µ-CHP unit and a condensing gas boiler revealed that the µ-CHP unit resulted in an annual cost saving of …
Transient And Quasi-Steady Thermal Behaviour Of A Building Envelope Due To Retrofitted Cavity Wall And Ceiling Insulation, Aimee Byrne, Gerard Byrne, Anna Davies, Anthony Robinson
Transient And Quasi-Steady Thermal Behaviour Of A Building Envelope Due To Retrofitted Cavity Wall And Ceiling Insulation, Aimee Byrne, Gerard Byrne, Anna Davies, Anthony Robinson
Articles
Accurate understanding of the thermal behaviour of building components is essential for predicting heat-ing or cooling needs and facilitates the implementation of more successful energy saving strategies and retrofits. This paper focuses on a specific measure commonly introduced through the residential energy efficiency retrofit programmes in Ireland–insulation. Traditionally, assessments of the performance of building envelopes have been based on assumed thermal resistances of the materials involved, labora-tory tests and computer modelling. The aim of the present work is to investigate the in situ thermal behaviour of a case study building and its components under transient and quasi-steady environmental conditions, comparing …
Rational Efficiency Of A Heat Exchanger, Jim Mcgovern, Brian P. Smyth
Rational Efficiency Of A Heat Exchanger, Jim Mcgovern, Brian P. Smyth
Articles
The authors propose a new and unique definition for the rational efficiency of a heat exchanger. This new rational efficiency is defined in terms of its sub-rational efficiencies: a heat transfer rational efficiency and a friction rational efficiency for each of the fluid systems comprising the heat exchanger. The heat transfer rational efficiency is based on the definition of a mean temperature for the heat source and a mean temperature for the heat sink and reflects the exergy supplied and the exergy received, due to heat transfer only. The friction rational efficiency for each fluid system of the heat exchanger …
Simulation Algorithm And Validation Of A Photovoltaic Water Pumping System, I. Odeh, Y. Yohannis, Brian Norton
Simulation Algorithm And Validation Of A Photovoltaic Water Pumping System, I. Odeh, Y. Yohannis, Brian Norton
Articles
A photovoltaic (PV) water pumping system has been modelled using TRNSYS considering a power supply, a direct current (DC)/alternating current (AC) inverter, an AC induction motor, a centrifugal pump, a well, a water storage tank, and an overflow protection device. The model emulates actual pumping head curves, uses numerical methods to determine pump system working points, and includes a storage tank as a component in the system. It simulates PV-powered water pumping systems, constant voltage tracking, voltage frequency modulation, and maximum power point tracking algorithms; variable inverter frequency with variable motor efficiency, variable inverter frequency with constant motor efficiency, and …
Heat Transfer Correlations For Low Approach Evaporative Cooling Systems In Buildings, Ben Costelloe, Donal Finn
Heat Transfer Correlations For Low Approach Evaporative Cooling Systems In Buildings, Ben Costelloe, Donal Finn
Articles
The experimental performance of an open industrial scale cooling tower, utilising small approach temperature differences (1–3 K), for rejection of heat at the low water temperatures (11–20 °C) typical of chilled ceilings and other sensible air–water heat dissipation systems in buildings, is examined. The study was carried out under temperate maritime climatic conditions (3–18 °C wet-bulb temperature range). Initially a theoretical analysis of the process at typical conditions for this climate was conducted, which indicated that a water to air (L/G) mass flow rate ratio of less than 1.0 was required for effective operation. Consequently for these low L/G ratios, …
Including Embodied Energy Considerations At The Conceptual Stage Of Building Design, Y. Yohanis, Brian Norton
Including Embodied Energy Considerations At The Conceptual Stage Of Building Design, Y. Yohanis, Brian Norton
Articles
Elevated operating temperatures reduce the solar to electrical conversion efficiency of building integrated photovoltaic devices (BIPV). Phase change materials (PCM) can be used to passively limit this temperature rise although their effectiveness is limited by their low thermal conductivities and by crystallization segregation during solidification. This paper presents an experimental evaluation of the effects of convection and crystalline segregation in a PCM as a function of efficiency of heat transfer within the finned PV/PCM system. The thermal performances of bulk PCM with crystallization segregation for different internal fin arrangements are presented. It is noted that the addition of internal fins …
Improved Direct Solver For Building Energy Simulation, Michael Crowley, Saleem Hashmi
Improved Direct Solver For Building Energy Simulation, Michael Crowley, Saleem Hashmi
Articles
Finite difference methods, when applied to the differential equations modelling energy flows in buildings, give rise to a system of non-linear difference equations. A frequently used direct solution method involving linearization is analysed and a related method proposed. These and one other connected method are compared using a building related test problem prepared for this purpose. The proposed numerical method is found to produce least error, about 30% less than the commonly used method, and it is recommended for inclusion in building energy simulation software. A fundamental method for estimating the pre conditioning period of a building, arising from the …
Evaluation Of Implicit Numerical Methods For Building Energy Simulation, Michael Crowley, Saleem Hashmi
Evaluation Of Implicit Numerical Methods For Building Energy Simulation, Michael Crowley, Saleem Hashmi
Articles
The stability of numerical methods used for finite-difference thermal modelling of buildings is discussed. A known instability in a commonly used process is described and alternative numerical methods with suitable stability properties are identified. With a view to selecting the optimum numerical method, the building energy simulation problem is characterized mathematically and appropriate implicit solvers are compared on the basis of accuracy and computational effort using a building related test problem prepared for this purpose. A recently developed numerical method with the necessary strong stability is found to possess higher computational efficiency than methods frequently used in this application and …