In the drive to build new homes to an exceptionally high standard, including energy efficiency, the spotlight has fallen on the off-site construction of modular homes. These buildings are constructed as much as possible in an off-site factory location, where a skilled workforce is permanently based, and quality can be controlled much more easily. The finished components are then shipped to the final build site for installation and assembly. Sweden, for example, is now building 45% of their new homes by this method and the UK is set to increase the percentage of homes it constructs by this modern method. While the quality of construction is higher, how can you assess the buildings performance in the real world as compared to the computer modelled figures? The answer for Step Places was to undertake some collaborative research with the University of Salford via the Energy House 2.0 Project. The University’s researchers undertook detailed measurements to assess the buildings actual performance.
The work the University of Salford undertook was in situ, over three weeks in the winter, when it could be guaranteed of a ten-degree Celsius temperature difference (∆T). This is necessary in some of the tests to obtain meaningful data. There were four main tests:
- Air Permeability Test – This checks the air leakiness of the property which has a major effect on the energy efficiency of the building. It does this by installing a blower door which pressurises and depressurises the sealed, as built, building and the data is collected on sensors and relayed to a laptop computer.
- Thermography – this used a high-quality thermographic camera which allowed any air leaks and thermal bridges to be identified.
- Whole House Heat Loss Test, or Coheating – This used a series of thermostatically controlled heaters, fans and data collection for internal temperature and conditions, external temperature, and energy consumption.
- U Value measurements of walls, floors, and ceilings – This used a standard rig which included heat flux sensors, surface temperature and air temperature sensors.
All this data was collected and eventually analysed to produce a report for Step Places. The property performed very well, exceeding current building regulations. The tests did reveal where some minor improvements could be made in terms of construction off site and the assembly process on site.
Gareth Smith, Director at Step Places said, “The work the University of Salford has undertaken for us at Wigan Pier has allowed us to validate our new design and highlight the areas to improve in an already very airtight shell for marginal improvements in key areas allowing us to use the data collated and be ready for when we roll out our next modular homes scheme in Rochdale later this year”.
For more information on Step Places, please visit: https://step-places.com/
Thermocill (KSR Consultancy NW Ltd)
Keith Rimmer of KSR approached the Energy House 2.0 team with a prototype of his ‘Thermocill’ product. This is a simple device that is fitted to under the window board of a window that sits directly above a central heating radiator which is the arrangement commonly found in most homes. KSR developed their own test rig which indicated a reduced heat loss through the window and quicker room heat up times that when the Thermocill device was fitted. Thermocill is a simple device that is easily fitted under the window board, directing rising warm air from the radiator onto the inside surface of the window.
The Thermocill device was tested in the thermal comfort laboratory within the Energy House; this is a single room with precisely controlled conditions and the aim of the testing was to assess the impact of the Thermocill on heat loss through a window and thermal comfort within the room.
Energy House researchers carried out a series of tests under precisely controlled conditions in the assessing three major factors:
- Heat flux through the window (a typical double glazed unit)
- Window surface temperatures
- Thermal comfort within the room (air velocity, RH, Black Globe temperature, air temperature)
- Room heat up times
The experimental set up is shown below:
(a) simplified schematic of measurement points and (b) experimental set up in the Salford Energy House thermal comfort laboratory.
The highlights from the testing were:
- At a room temperature set point of 21⁰C the Thermocill reduced the warm-up period in the laboratory by up to 23%. This improvement was not observed at a 23⁰C set point.
- Both U values and heat flux through the window were reduced with the Thermocill; 3% (from 1.71 W/m2K to 1.65 W/m2K) at room set point of 21 °C and by 2% (from 1.73 W/m2K to 1.69 W/m2K) at 23 °C.
- Heating energy for the room was reduced by Thermocill, under the test conditions, the savings could be up to 16% at 21 °C and 3% at 23 °C.
KSR have applied for a patent with the and intention of large-scale manufacture and a product launch. Discussions underway with Energy House 2.0 researchers about work in the following areas:
- Extrapolation of the results obtained from the thermal comfort laboratory to a typical house.
- Modelling of air flows in order to understand the heat transfer mechanisms and optimise the Thermocill design
- Monitored field trials.
Homely Energy Ltd
As part of the ERDF- supported Energy House 2.0 project, the Homely system was tested in the Smart Meters>Smart Homes Laboratory at the University of Salford which has a choice of heating systems available, including an Air Source Heat Pump (ASHP). A test compared two 24-hour periods with and without the Homely control system. With electricity priced according to the Octopus Energy dynamic tariff, the external temperature, room temperature, electricity demand, and cost were recorded. During the test period external temperatures were between 5 and 10⁰C and comparison of the two test periods showed that approximately 20% cost savings were achieved with the Homely system. This was despite the fact that external temperatures were lower during the 24-hour period where the Homely control app was used.
Homely Energy Ltd is a start-up business based in Manchester and has developed a control algorithm for heat pumps, which allows consumers to fully benefit from dynamic electricity tariffs. Homely supply a specially designed thermostat that is controlled via an app with the aim of reducing the running costs of the heat pump without impacting on the thermal comfort of the householder. Taking into account time of day, consumer energy use patterns, consumer comfort preferences, external temperatures, and the electricity tariff, the algorithm automatically adjusts the room temperature set points.
Karolis Petruskevicius, Managing Director, Homely Energy commented, “The Smart Meters>Smart Homes laboratory provided the ideal test bed for the Homely system and has provided us with extremely valuable data which we used to further refine and develop our product. The support of the Salford academics, in particular Dr Ioannis Paraskevas, was also crucial to the success of this trial. Subsequently, we have been able to start conversations with a number of potential partners, such as heat pump manufacturers and installers, to launch our product with the expectation that a number of householders will benefit from lower energy costs.”
Further details about Homely Energy can be found on their website, www.homelyenergy.com