scholarly journals Space heating operation of combination boilers in the UK: The case for addressing real-world boiler performance

2018 ◽  
Vol 40 (1) ◽  
pp. 75-92 ◽  
Author(s):  
George Bennett ◽  
Cliff Elwell ◽  
Tadj Oreszczyn

Residential space and water heating account for 23% of UK final energy demand and combination gas boilers are the dominant technology. Performance gap issues in gas boiler systems have been reported, with previous studies unable to isolate or quantify root causes for performance issues, hampered by indirect and coarse measurement methods. Utilising high-frequency data, through state-of-the-art boiler diagnostics from 221 UK combination boilers, assumptions in efficiency standards are challenged. Total heating energy consumption and number of hot water tappings are in line with national expectations but the observed cycling behaviour of boilers gives cause for concern due to links with lower performance and higher emissions. Most combi-boilers appear oversized for space heating and despite available modulation are unable to prevent rapid on–off cycling. Per day, half of combi boilers studied average more than 50 starts and 70% of starts average less than 10 min during space heating operation. Cycling contradicts assumptions in efficiency testing standards, which assume steady state operation, weighted by full and part power measurements. Addressing oversizing and excessive boiler cycling provides an opportunity to quickly and significantly reduce emissions associated with heating, at low cost through the ongoing replacement of millions of boilers. Practical application: Lessons learned from this research regarding the detrimental performance issues seen in gas combi boilers are directly applicable to the topics of boiler specification for building service engineers and installers, such as guidelines in CIBSE Guide A, 1 CE54 Whole house boiler sizing method 2 and legislation set out in BoilerPlus from the Department of Business, Energy and Industrial Strategy. Plant size ratio, radiator hydraulic layout and controls can all contribute to the rapid cycling seen in the data and can all be influenced by building service professionals. Boiler modulation range is also crucial and manufacturers need to be aware of the benefits of extending modulation in new products.

2020 ◽  
Vol 41 (6) ◽  
pp. 709-726
Author(s):  
George Bennett ◽  
Cliff Elwell

Gas boilers dominate domestic heating in the UK, and significant efficiency improvements have been associated with condensing boilers. However, the potential remains for further efficiency improvement by refining the control, system specification and installation in real dwellings. Dynamic building simulation modelling, including detailed heating system componentry, enables a deeper analysis of boiler underperformance. This paper explores the link between the space heat oversizing of boilers and on/off cycling using dynamic simulation, and their subsequent effect on boiler efficiency and internal temperatures. At plant size ratio (PSR) 8.5 daily cycles numbered over 50, similar to median levels seen in real homes. Simulations show that typical oversizing (PSR >3) significantly increases cycling behaviour and brings an efficiency penalty of 6–9%. There is a clear link between raising PSR, increased cycling and an associated decreased efficiency; however, in the UK, boilers are regularly oversized with respect to space heating, especially combination boilers to cover peak hot water demand. Current legislation and labelling (ErP and SAP) overlook PSR as a determinant of system efficiency, failing to incentivise appropriate sizing. Reducing boiler oversizing through addressing installation practices and certification has the potential to significantly improve efficiency at low cost, decreasing associated carbon emissions. Practical application: This research provides the basis for a practical and cost effective means of assessing the potential for underperformance of boiler heating systems at the point of installation or refurbishment. By assessing the oversizing of the boiler with respect to space heating, unnecessary cycling and the associated efficiency penalty can be avoided. Plant size ratio, as an indicator of cycling potential, can be implemented in energy performance certificates (EPCs), through the standard assessment procedure (SAP), using existing data. The potential for real carbon savings in the existing boiler stock is considerable, and the findings have wider implications for next generation heating systems.


Author(s):  
Bernd Weber ◽  
Jessica A. Fernández Valdespino ◽  
David García ◽  
M. Dolores Durán ◽  
Iván G. Martínez Cienfuegos ◽  
...  

In order to meet global challenges to reduce greenhouse gas emissions, the implementation of solar systems for residential purposes is an emergent task. Commonly liquid-based solar systems are used to heat up shower and pool water. More recently space heating systems have become part of sustainable buildings. An alternative could be a solar system that uses air as energy carrier. This study analyses the retrofit of such a system into a 40-year-old building. Starting from the analysis of the energy demand of a selected room, a solar air heater was designed, simulated and evaluated experimentally. The solar efficiency of the constructed collector reached 60%.


2021 ◽  
Vol 2069 (1) ◽  
pp. 012115
Author(s):  
Katarina Simic ◽  
Klaas Thiers ◽  
Hugo Montyne ◽  
Jan Desmet ◽  
Michel De Paepe

Abstract Residential buildings claim a significant share of the total energy use worldwide. In order to have more realistic energy performance predictions, increased attention is paid to the analysis of the building’s energy use through comprehensive, transient detailed numerical simulations. In this article, the self-consumption and self-sufficiency values of three detached residential buildings are assessed through numerical models made in the programming language Modelica and software tool Dymola. The three buildings have the same structure and different space heating energy demands of 15 kWh/m2year, 30 kWh/m2year and 45 kWh/m2year. The energy use of the buildings coincides with the occupancy profile where domestic hot water use dominates over the space heating demand provided by an air to water heat pump. The discrepancy between renewable energy production and energy consumption is mitigated by means of thermal load shifting and electrical energy storage. In this research, the self-consumption and self-sufficiency of the studied buildings have been analysed as a function of the economically favourable energy storage sizing. For the use of an electrical battery with the installed capacity of 2.5 kWh and thermal energy storage of 250 l, the self-sufficiency results to be 40%, 38.5% and 37% for the three buildings respectively at the specific simulated energy demand conditions.


Energies ◽  
2021 ◽  
Vol 14 (4) ◽  
pp. 1012
Author(s):  
Francesco Calise ◽  
Francesco L. Cappiello ◽  
Maria Vicidomini ◽  
Jian Song ◽  
Antonio M. Pantaleo ◽  
...  

In this research, a technoeconomic comparison of energy efficiency options for energy districts located in different climatic areas (Naples, Italy and Fayoum, Egypt) is presented. A dynamic simulation model based on TRNSYS is developed to evaluate the different energy efficiency options, which includes different buildings of conceived districts. The TRNSYS model is integrated with the plug-in Google SketchUp TRNSYS3d to estimate the thermal load of the buildings and the temporal variation. The model considers the unsteady state energy balance and includes all the features of the building’s envelope. For the considered climatic zones and for the different energy efficiency measures, primary energy savings, pay back periods and reduced CO2 emissions are evaluated. The proposed energy efficiency options include a district heating system for hot water supply, air-to-air conventional heat pumps for both cooling and space heating of the buildings and the integration of photovoltaic and solar thermal systems. The energy actions are compared to baseline scenarios, where the hot water and space heating demand is satisfied by conventional natural gas boilers, the cooling demand is met by conventional air-to-air vapor compression heat pumps and the electric energy demand is satisfied by the power grid. The simulation results provide valuable guidance for selecting the optimal designs and system configurations, as well as suggest guidelines to policymakers to define decarbonization targets in different scenarios. The scenario of Fayoum offers a savings of 67% in primary energy, but the associated payback period extends to 23 years due to the lower cost of energy in comparison to Naples.


Author(s):  
Hamid Aghaie

Austrian district heating (DH) has experienced a fast increasing trend for the last 30 years (with the exception of the period 2010-2014), resulting in a triplication of delivered heat; in the year 2018, with about 2400 networks and 20 TWh supply, DH covered 6.4% of the final energy consumption (1122.5 PJ). Worth to underline is also that this growth of Austrian district heating has been about twice faster than the one of the energy demand in the same period. Currently, district heating provides about 26% of the Austrian households with the energy requested for space heating and domestic hot water preparation.


2014 ◽  
Vol 55 (65) ◽  
pp. 59-73 ◽  
Author(s):  
Martin J. Siegert ◽  
Keith Makinson ◽  
David Blake ◽  
Matt Mowlem ◽  
Neil Ross

AbstractIn the early hours of 25 December 2012, an attempt to explore Subglacial Lake Ellsworth, West Antarctica, using a specially designed hot-water drill, was halted. This UK project, involving several universities, the British Antarctic Survey and the National Oceanography Centre, had been in planning for 10 years. The project developed a full blueprint for subglacial lakes research, involving access to the subglacial environment through deep drilling, direct measurement and sampling of water and sediment by the construction of a probe and sediment corer, and environmental protocols to ensure cleanliness in line with international agreements on stewardship and protection of subglacial systems. Drilling was ceased after the main borehole failed to link with a subsurface cavity of water, built up over ∽40 hours. Without this link, insufficient water was available to continue drilling downwards to the lake, ∽3000 m beneath the surface. On return to the UK, an external review of the programme was undertaken to formally assess the reasons for the fieldwork failure, and to make recommendations on the modifications necessary for success. From this review, the Lake Ellsworth programme formulated a pathway along which a second attempt to explore the lake can be developed. Here details of the Lake Ellsworth field experiment, the circumstances that led to its failure and the corrections required are presented. Hot-water drilling is still regarded as the only feasible scheme for assuring clean access to the subglacial environment. The lessons learned from the Lake Ellsworth experience are substantial, however, and demonstrate that considerable technological and methodological advances are necessary for successful future research on subglacial lakes beneath thick (>2 km) ice.


1996 ◽  
Vol 33 (3) ◽  
pp. 211-222 ◽  
Author(s):  
D. W. M. Johnstone ◽  
N. J. Horan

From the middle ages until the early part of the nineteenth century the streets of European cities were foul with excrement and filth to the extent that aristocrats often held a clove-studded orange to their nostrils in order to tolerate the atmosphere. The introduction in about 1800 of water-carriage systems of sewage disposal merely transferred the filth from the streets to the rivers. The problem was intensified in Britain by the coming of the Industrial Revolution and establishment of factories on the banks of the rivers where water was freely available for power, process manufacturing and the disposal of effluents. As a consequence the quality of most rivers deteriorated to the extent that they were unable to support fish life and in many cases were little more than open sewers. This was followed by a period of slow recovery, such that today most of these rivers have been cleaned with many having good fish stocks and some even supporting salmon. This recovery has not been easy nor has it been cheap. It has been based on the application of good engineering supported by the passing and enforcement of necessary legislation and the development of suitable institutional capacity to finance, design, construct, maintain and operate the required sewerage and sewage treatment systems. Such institutional and technical systems not only include the disposal of domestic sewage but also provisions for the treatment and disposal of industrial wastewaters and for the integrated management of river systems. Over the years a number of institutional arrangements and models have been tried, some successful other less so. Although there is no universally applicable approach to improving the aquatic environment, many of the experiences encountered by the so-called developed world can be learned by developing nations currently attempting to rectify their own aquatic pollution problems. Some of these lessons have already been discussed by the authors including some dangers of copying standards from the developed world. The objective of this paper is to trace the steps taken over many years in the UK to develop methods and systems to protect and preserve the aquatic environment and from the lessons learned to highlight what is considered to be an appropriate and sustainable approach for industrialising nations. Such an approach involves setting of realistic and attainable standards, providing appropriate and affordable treatment to meet these standards, establishment of the necessary regulatory framework to ensure enforcement of the standards and provision of the necessary financial capabilities to guarantee successful and continued operation of treatment facilities.


2021 ◽  
Vol 8 (1) ◽  
Author(s):  
Martin Pullinger ◽  
Jonathan Kilgour ◽  
Nigel Goddard ◽  
Niklas Berliner ◽  
Lynda Webb ◽  
...  

AbstractThe IDEAL household energy dataset described here comprises electricity, gas and contextual data from 255 UK homes over a 23-month period ending in June 2018, with a mean participation duration of 286 days. Sensors gathered 1-second electricity data, pulse-level gas data, 12-second temperature, humidity and light data for each room, and 12-second temperature data from boiler pipes for central heating and hot water. 39 homes also included plug-level monitoring of selected electrical appliances, real-power measurement of mains electricity and key sub-circuits, and more detailed temperature monitoring of gas- and heat-using equipment, including radiators and taps. Survey data included occupant demographics, values, attitudes and self-reported energy awareness, household income, energy tariffs, and building, room and appliance characteristics. Linked secondary data comprises weather and level of urbanisation. The data is provided in comma-separated format with a custom-built API to facilitate usage, and has been cleaned and documented. The data has a wide range of applications, including investigating energy demand patterns and drivers, modelling building performance, and undertaking Non-Intrusive Load Monitoring research.


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