1.0 Introduction A study was carried out to revisit some of the widely-applied conventions of system solutions to identify opportunities for improvement. This paper describes a joint-study to review the various heating systems typically encountered in the industry today. The study is based on a real life large student accommodation where the application of various combinations of gas and electricity space heating and hot water systems were investigated to determine the respective system capital and lifecycle operational costs, fuel consumption and CO2 emission over a 20-year period. 2.0 Systems The study compared the baseline system solution of Low Temperature Hot Water (LTHW) gas boiler for space heating and domestic hot water (DHW) generation against alternatives of Table 1 Solution options investigated Space heating Baseline LTHW with gas boiler Option 1 LTHW with gas boiler Option 2a Electric resistance Option 2b Electric resistance Option 3a LTHW with air source heat pump Option 3b LTHW with air source heat pump continuous ow water heaters, electric heating and air source heat pumps. Table 1 outlines the options that were considered. Domestic hot water (DHW) Indirect storage with gas boilers Continuous ow water heater Electric resistance Continuous ow water heater Air source heat pump Continuous ow water heater 3.0 Building heating demand The student accommodation block estimated space heating demand was generated using a dynamic thermal model, which equates to 445 MWh/pa excluding storage and distribution losses. The model was run with CIBSE Test Reference Year for London, and complies with the UK Building Regulations Part L 2013 requirements. The pipe heat loss are applied to the corridors and risers and varied seasonally with the heating demand and adjusted for both mean corridor temperatures as well as for weather compensation. The daily DHW demand is based on a usage rate of 70 l/person/day and a total of 643 persons, amounting to 1733kWh/day (55K lift). The DHW demand varied seasonally corresponding to typical university term and the incoming cold water temperature is varied in-line with the average ground temperature at 1.5m deep. Overall the annual demand for DHW is around 536 MWh/year, before allowing for storage and distribution losses. For more details on RINNAI products visit www.rinnaiuk.com 80 November 2019 www.cibsejournal.com Advertisement Feature p80.CIBSEMagNOV19.indd 80 22/10/2019 15:20