PASSIVE SOLAR RETROFIT OF THERMALLY SUBSTANDARD HOUSING AT EASTHALL, GLASGOW

Objetivo

The underlying aim of the project is to demonstrate a large reduction in heating costs and elimination of condensation dampness in 36 thermally substandard local authority houses. This is the first major retrofit in Scotland to achieve this end with the assistance of passive and hybrid solar techniques, the specific technical aims of which are :
1) Having insulated to a high standard (60% reduction on specific heat loss), glazed buffer spaces, with a strong ventilation preheat role, enable further significant savings bringing space heating loads down to 20% of existing base case.
2) Twin buffer spaces on opposite facades enable performance parity for randomly oriented existing housing, and relatively frequent, but energy efficient, air change is achieved.
3) Solar air collectors and heat exchangers preheat water in summer, and enhance air in access stairs.
Predicted total saving is approximately 500 MWh p.a. for 36 houses, with payback of 16 years.
Installation of Squirrel dataloggers etc. completed Sep. 1992 - 1st data recorded 19/2/1992 i.e. approx. 4 months behind Annex 1 programme; air collector system tested and operational - source of air-leakiness identified and rectified; Building Contractor now completed snagging items; early measurements indicated a settling-in period with respect to controls of heating system, with temperatures tending to be higher than needed for comfort; living rooms and main bedrooms in particular heated to a higher temperature than predicted (based on 21 deg. C demand); user control of windows/doors between sunspaces and heated rooms in autumn and spring often negates buffer effect during parts of the day - the solar strategy is then one of 'direct gain' with an extended heated volume; heating system controls allow users scope to 'mis-use' - e.g. quite high non-storage diurnal heating in some electric houses; currently analysing trends from measured data, correlated to questionnaire/log-book information with respect to user-intervention/lifestyle etc.; it has now been established that performance tends much as predicted or better during central winter period (December to February), once adjustment has been made for measured temperatures; this implies that buffers are operating well as heat exchangers with respect to ventilation during this period - one fairly close fit identified the actual daily ventilation rate as close to 1.5 ac/h; while the effective rate (allowing for the preheating effect) was 1.11 for the whole heating season, 0.99 from Sep-Nov, 1.07 from Dec-Feb and 1.26 from March-May. Third Contractor, Technical Services Agency in receivership 1992, but this will not affect advancement of project. Note also some data lost from Oct-Nov 1993 due to theft of portable computer while down-loading, this was subsequently recovered with data still intact.
Analysis complete, and dissemination under way: papers published in proceedings of 3 international conferences todate and abstract accepted for ISES Solar World Congress in Harare, Sep. 1995; series of international seminars planned early 1996 with local Glasgow OPET (NIFES); detailed report complete and attached with this submission; summary booklet ready for issue June 1995.
1) INNOVATIVE TECHNOLOGY
a) This is an innovative application of an existing technology, in that it has never been applied and evaluated in the context of thermally substandard public sector housing stock in Scotland.
b) Climate parameters do not favour direct gain passive solar solutions, gain loss ratio reducing with increasing UK latitude; but analysis shows that glazed buffer spaces can reverse this trend.
c) As insulation gives reducing energy return with increasing thickness, application of glazed buffer spaces, with emphasis on preheating of ventilation air, yields a further significant saving.
d) Ventilation preheating recognises that most of the temperature rise in the glazed buffer space in winter is due to space heating loss from the house, constituting then a basic form of heat recovery.
e) Glazing in existing recessed verandahs also eliminates awkward cold bridges, and a second glazed extension on the opposite facade enables performance parity for random existing orientations.
f) Due to relatively high life-cycle costs, and operational unknowns in rented sector, night insulation has been omitted from analysis; and hence represents a departure from passive solar norm.
g) Having reduced space heating loads to 20% of existing base case, 25-30% reduction of water heating is predicted by means of a shared air collector with air-to-water heat exchanger.
2) THE CONTEXT IN WHICH THE TECHNOLOGY IS OPERATING
The proposed demonstration project on a relatively exposed flat and south sloping site, around 75m altitude, comprises 30 years old, 3-storey, 3-apartment local authority tenements in semi-traditional construction, with groups of 6 houses served by common access stairs. Each house currently has an west or south-east facing recessed verandah/balcony, but twin buffers accommodate all orientations.
The origin of the project in community technical aid, a community hosted ideas competition, and continued client group participation/control is a motivatingforce, relevant to technological outcome.
3) ECONOMIC ASPECTS OF TECHNOLOGY
Objective economic analysis is complicated by overlapping underlying needs/functions served by key improvement measures. For example, external insulation:- energy saving + weatherskin; twin glazed buffer spaces:- passive solar strategy + extra floor space + removal of moisture producing activities.
Further, if particular improvement measures are isolated in terms of capital cost and energy saving, theoretical payback may be untenable - e.g. if glazed extension had to be repaid in energy saving.
4) MONITORING IF OF PARTICULAR NOTE
The aims of monitoring are as follows: - a) to identify the total energy saving attributable to all measures taken in the 36 demonstration houses compared with the same number of unaltered references on the same site; b) to isolate the space heating saving due to specifically to the glazed verandah and conservatory, and the solar component of this saving.

Programa(s)

ENG-ENDEMO C - Programme (EEC) of demonstration projects and industrial pilot projects (EEC) in the energy field, 1985-1989

Tema(s)

7.2 - THERMAL

Convocatoria de propuestas

Data not available

Régimen de financiación

DEM - Demonstration contracts

Coordinador

EASTHALL RESIDENTS ASSOCIATION

Aportación de la UE

Sin datos

Dirección

COMMUNITY HALL WARE ROAD
GLASGOW G
Reino Unido

Coste total