PART 2 : NON-TECHNICAL BUILDING DESCRIPTION
Single storey earth-sheltered building
‘Dial Corner’ is a single storey earth-sheltered building designed to be naturally heated and naturally ventilated, without recourse to burning fossil fuels. This will better prepare the home and the household for a time when these resources become scarce and uneconomical to use.
The energy efficiency and carbon mitigation standards achieved by Dial Corner are among the highest recorded in the UK. These standards are verified by third parties; CNC Building Control and Elmhurst Energy Services Ltd. Dial Corner can be described as operating beyond ‘zero carbon’. This claim can be made due to the proposed building having achieved an exceptional Design SAP Rating of 167A. A SAP (Standard Assessment Procedure) Rating is the value given to energy efficiency and carbon emissions in calculating the EPC (Energy Performance Certificate) To put this rating in context, the average UK dwelling SAP Rating is 60D and the average newbuild home achieves a SAP Rating of 80B. The UK Government’s former definition of a ‘Zero Carbon’ dwelling had to achieve a 100A SAP Rating. Of the 15million EPC’s registered in the UK, Dial Corner’s EPC, once built, will be in the top 0.001%, making this a truly exceptional, one in a million building.
High performing buildings that Dial Corner learns from and improves upon is the Honingham Earth-Sheltered Social Housing Scheme, the 2006 International RICS Sustainable Building of the Year. The dwellings are 11 miles from Suton. Honingham’s SAP Ratings are 87 with no renewable energy generation, less insulation, no rainwater harvesting and double, not triple, glazed windows. Being naturally heated, this home requires no conventional central heating system; no gas or oil central heating boilers, no radiators, no ground source or air source heat pumps. Dial Corner will emit neither carbon nor greenhouse gases from using fossil-fuels. Heat from the sun, heat from human occupants and heat from household appliances (fridges, freezers, cookers, TV’s etc) replace the need for conventional heating. Heat from these sources is stored in the cement free concrete walls, floor and roof, each performing as large storage radiators; a ‘heat sink’. Internal air temperatures will remain stable throughout the year, around 21degrees centigrade. Heat stored in the building walls, roof and floor will be released in to the rooms at times when the temperature outside the building is lower than inside. This transfer of heat is a natural characteristic of what are referred to as ‘high thermal mass’ buildings. More heat is retained within the building fabric longer when more insulation is applied.
As a naturally ventilated home, the building uses passive stack vents and cross ventilation. There are no mechanical ventilation systems, nor mechanical air conditioning. The home will be ventilated with fresh air from trickle vents, sliding vents and opening windows.
With no reliance on mechanical devices for heating and ventilation, Dial Corner will use significantly less electricity, burn no carbon, have no maintenance, servicing and nor any capital replacement of equipment. For these reasons the property can be described as having a ‘low cost of ownership’.
Increased biodiversity is achieved by the grass covered earth-bunded walls and the sedum green roof also increasing habitats, flora and fauna. These building landscape features will increase carbon sequestration for the lifetime of the building where conventional buildings don’t. Other benefits of the earth covering include increases in sound insulation as well as improving thermal insulation. Better insulated than the majority of homes built today, Dial Corner will have 500mm (1ft 8inches) of insulation under the floor and 300mm (12inches) to the walls and roof. Triple-glazed windows reduce heat loss from windows by half,‘DIAL CORNER’ PLANNING STATEMENT 21st DECEMBER 2021 compared to conventional double-glazed windows.
Generating more electricity than it will use, Dial Corner’s 20KW of ground mounted photovoltaic (pv) panels (57 solar panels) will produce approximately 16,000units of renewable energy each year, three times as much energy as required. 20KWpeak of pv’s is estimated sufficient energy generation for the peak winter demands of the household. A Tesla 13.5KW Power Wall will allow some of the surplus electricity to be stored for use at night and for charging an electric car. Unused electricity generated by the photovoltaic panels will be sold back to the National Grid. The design includes an office and craft workshop, which will enable the residents to work from home. These two rooms could easily be adapted to additional bedrooms should the need arise in the future.
