Cracking the Code Energy and CO 2 Malcolm

Cracking the Code: Energy and CO 2 Malcolm Bell Buildings, Energy and Sustainability Group, School of the Built Environment, Leeds Metropolitan University, Leeds, UK. Paper presented to: The Code for Sustainable Homes: Cracking the Code Seminar - 14 March 2007, Birmingham, UK.

Racking up the energy/CO 2 points

Target Emission Rate – the TER Target Emission Rate kg (CO 2)/m 2/a partially offsets higher carbon intensities of fuels other than gas (electricity, oil, lpg etc. CO 2 emissions for lighting TER = (CH x fuel factor + CL) x (1 - Improvement) CO 2 emissions for ventilation, and space & water heating for the notional dwelling Improvement factor = 0. 2 i. e. a 20% reduction

The TER thresholds

Target Emission Rate – the TER

TER - Threshold values - 10% - 18% - 25% - 44% circa -135% to -150% ? ?

The TER points scale

TER – Threshold compliance packages 80 m 2 Semidetached 2 storey house

TER – Base Case TER-06 - electricity TER-06 - gas & bio Bio: would meet the threshold for 4 Star = 12. 9 code points

TER – 1 (-10%) TER-06 - electricity TER-06 - gas & bio

TER – 2 ( -18%) TER-06 - electricity TER-06 - gas & bio

TER – 3 (-25%) TER-06 - electricity Target = 24. 77 Actual = 24 TER-06 - gas & bio

TER – 4 (-44%) TER-06 - electricity Target = 18. 49 Actual = 17 TER-06 - gas & bio

Passive House Standards Timber frame scheme Göteborg, Sweden (120 m 2) Source: Wall (2006), Photo: Hans Eek MVHR – 80% with duct heaters Airtightness 1 m/h 5 m 2 Solar water + resistance top-up

Passive House Standards Timber frame scheme Göteborg, Sweden Source: Wall (2006), Photo: Hans Eek TER (kg. CO 2/m 2) Design ≈ 10. 6 Actual ≈ 15. 3 Under Swedish conditions! Source: Wall (2006), Energy and Buildings. 38, pp 627 -634

TER – 5 (-100%) TER-06 - electricity TER-06 - gas & bio Net TER = 0

TER – 6 (-135% to -150%) Appliances

The place of energy & CO 2 One of many scenarios Note: “Other energy” is modelled to balance TER & other energy points in each class

Models and Management Stafford Beer’s presidential address to the Society for General Systems Research at the Annual Meeting of the American Association for the Advancement of Science, 1971 (Beer 1973)

Managing the world ? Management Model Reality

The effects of time Management Model ? Reality Time

Feedback on performance: Airtightness

Hidden air paths Behind plasterboard

Hidden air paths Internal partitions

Thermal bridging & construction Designed performance is almost always degraded

Construction issues: window lintel As Designed = 42 mm gap Ψ value = 0. 068 W/m. K Typical As Built = 20 mm gap Ψ value = 0. 180 W/m. K +164%

Understanding complex heat loss paths Party wall heat bypass

Cracking the Code? ? Only if we use it to manage the real world