Community Energy Literature Review

Introduction During a recent online forum about the UK’s Warm Homes Plan, a question was asked about the role of air-to-air heat pumps in low-carbon heating policy. The UK plan will be briefly outlined below, followed by a discussion of the advantages and disadvantages of air-to-air heat pumps compared to air-to-water heat pumps, based on an EIRO publication. The Warm Homes Plan 2026 The plan is discussed in relation to the housing sector in an article from the Carbon Literacy Project (CLP, 2026). “Homes and buildings account for roughly one-fifth of UK emissions” and £15 billion is to be invested with the aim of upgrading five million homes by 2030. The existing Boiler Upgrade Scheme will continue to offer grants of up to £7,500 per property for installation of heat pumps and a “£2,500 grant per property will also be available for air to air (as opposed to air to water) heat pumps which can also provide cooling.” The UK Warm Homes Plan (DESNZ, 2026) notes the increase in sales...

Introduction The use of digital twins in the planning, construction and operation of buildings was outlined in the previous post. The following discussion touches on the use of genetic algorithms and related software to optimise building design and performance. A selection of papers describing the use of genetic algorithms in this way will be cited together with references to background information. Genetic Algorithms The origins of software based on natural selection have been traced back to early computer scientists such as Alan Turing, John Von Neumann and Norbert Weiner (Mitchell, 1995). Genetic Algorithms (GAs) have found application in many areas where more conventional methods are difficult to apply, such as problems involving many variables. The ‘solutions’ proposed by a GA need to be evaluated, and this may require additional software specific to the problem in hand, in this case the computer modelling of buildings. Building Information Modelling The history of build...

Introduction The idea of a digital twin may stem from the explosion of an oxygen tank in the Apollo 13 space mission of 1970. “NASA employed multiple simulators to evaluate the failure and extended a physical model of the vehicle to include digital components. This “digital twin” was the first of its kind, allowing for a continuous ingestion of data to model the events leading to up to the accident for forensic analysis and exploration of next steps” (NASA, 2021). The importance of accurate digital models is clear in programs such as Artemis, which is intended to facilitate missions to Mars, when the constant communication needed to allow human intervention in case of problems will not be available. Digital twins also have many earth-bound applications such as product research and design, replacing costly prototypes; supply chain operations, giving manufacturers a comprehensive view of logistics, operations and potential bottlenecks; collecting data about products and their use, al...

In May and June 2019 four short articles on this blog discussed heat loss from buildings through air changes, air quality in buildings, and methods of measuring rates of air change.  “ A Change of Air” noted that an appreciable proportion of the total energy supplied to a building may be lost through excessive air change rates and outlined methods of measuring the rates through pressure testing, energy balance calculation, and CO2 decay. “Indoor air quality” described the main groups of pollutants which affect indoor air quality, and “CO2 in the Home” discussed indoor CO2 levels, how they might affect the health of occupants, and their measurement.  CO2 decay methods and their limitations were discussed in more detail in “Measuring Air Change Rates by CO2 Decay”. More recent work will be outlined below, referencing papers published from 2021 to 2024. Nazaroff (2021) presented a review of field studies that measured residential air-change rates. These were mainly in north Am...

    On 13 June the successful launch of the HOTSAT-1 satellite was reported by the SatVu company (SatVu, 2023a). It was described as the first of eight planned satellites which because of their “unique thermal imaging capabilities” would provide a “valuable and unique insight into economic activity and energy efficiency for a range of industries aligning with global Net Zero goals.” During February of the previous year Alex Conacher (2022) wrote that “British satellite company Satellite Vu has signed a deal with SpaceX to launch its satellites into low earth orbit in early 2023. The company’s satellites collect thermal data of the built and natural environment and are capable of measuring the heat signature of a building several times per day.” Prior to the launch SatVu explained that the “pioneering space technology” had already been deployed in a UK test flight which showed its potential to map heat loss from houses, identifying “buildings most in need of retrofittin...

          According to the International Energy Agency, “50% of global final energy consumption in 2018” was used in heating, contributing 40% of global CO2 emissions (IEA, 2019). Just under half of the heat “was consumed in buildings for space and water heating and, to a lesser extent, for cooking”. These figures help to explain the interest in retrofitting existing buildings to improve their thermal efficiency. The process can be difficult and expensive, and a variety of approaches has been taken. In the work outlined below, the role of software will be given particular attention. Foda,   El-Hamalawi and Le Dréau (2020) describe “a computational analysis taking a French single family house as a case study” using dynamic thermal modelling to find the optimum balance between annual energy saving and the cost of standardised retrofit measures available on the French market. The house had four occupants; was detached and typical of those built before 1974...

The UK Government’s Green Homes Grant scheme (GOV.UK, 2020) may have had some success in that it motivated some home owners to think about how they would make energy improvements to their homes if they could find a suitable contractor and received a grant.   One of the measures included in the scheme was the installation of a heat pump, of either the ground or air source type. Within the scheme these devices were classified as low carbon heat measures, and were subject to additional requirements. One was that a “minimum level of insulation is recommended to ensure the proper design and operation of the relevant technology in line with relevant standards” and another that all “heat pump systems must have a minimum Seasonal Performance Factor (SPF) of 2.5.” Ofgem (2021) defines the SPF as “a measure of the operating performance of an electric heat pump heating system over a year. It is the ratio of the heat delivered to the total electrical energy supplied over the year.” Ofgem exp...