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Renewable Energy Design Statement Proposed Extensions and Refurbishment for Lea Rowing Club The Boathouse, Spring Hill, Clapton, London E5 9BL Report Prepared by Richard Bonshor RIBA 3 Church Close Bucklesham 01473 659915 [email protected] Scope of Report This document has been prepared to accompany the planning application to extend and partially rebuild Lea Rowing Club based upon the scheme shown on the application drawings. The report is limited in scope to reflect the design at its current level of detail. In some sections it provides a statement of intent to demonstrate how a particular aspect of design or approach to a sustainable energy strategy has been considered but which will only be fully documented or detailed when the construction stage of the development is reached. It would be unreasonable to require financial expenditure proceeding to a detailed design phase until such time as a (conditional) planning permission had been granted. It is expected that conditions could be attached to any consent requiring submission of further details or information where that is considered necessary to further substantiate the energy use of the development. 1. General Approach and Overview There is a commitment to minimize the energy demands of the development (and hence future running costs). Wherever it is financially viable to do so, this will be over and above the requirements of the Building Regulations. Given that much of the funding for the proposed development will come from general ‘fundraising’ rather than existing capital, we will judge the (additional) capital outlay required against a 15 year initial ‘payback’ period. The existing site comprises three buildings, the café, Tyrell’s boathouse and the main boathouse. No significant works are proposed to the first two buildings, the café is a stand alone building and Tyrell’s is used only for boat storage and is unheated. It is the main boathouse and ancillary areas which are to be extended and upgraded as part of this application and it is those areas which are addressed within this report. 2. Existing Buildings: 2.1 Boat storage areas are unheated and lighting is by fluorescent tube fittings. Other building areas are heated via a LPHW system and hot water is provided via a gas boiler and hot water storage cylinders. The existing building fabric has minimal insulation to walls, and the existing industrial (profiled fibre cement) roofing and separating floor over the unheated boat storage areas. The building has a mixture of light fittings but fluorescent fittings predominate. 2.2 The parts of the existing building (remaining as part of the re-development) will be enclosed on two faces by the new/ rebuilt parts of the site. In addition it is planned that the remaining external walls and roof will be substantially over hauled with new double glazed windows, roof lights and doors, together with upgrading of the thermal insulation to exposed and semi-exposed elements to at least current Building Regulation standards. This in itself will dramatically reduce the requirements for space heating within the existing buildings which are to be retained. 3. New Buildings: 3.1 It is proposed that a ‘fabric first’ approach is the starting point for the energy policy for the new sections of the building. The detailed construction specification will exceed the current requirements of the Building Regulations for levels of insulation, air tightness and ventilation. In addition provision will be made to include mechanical ventilation and heat recovery (MVHR). The existing gas boiler is relatively new and was sized to supplement the additional space proposed by the new development. There will be a need to incorporate additional zone controls and timers to allow for maximum flexibility within the new development. 3.2 Energy efficient lighting will be installed throughout the development, with provision for generous natural light via windows, roof lights and glazed doors wherever possible and practical to suit the room layouts. 3.3 Kitchen fittings lift installation, electric equipment and ancillary fittings will all be required to achieve a class A energy rating. 4. Renewable Energy: The different sources of renewable energy have been considered to complement a highly insulated building fabric together with the particular constraints of the site and existing buildings. 4.1 Solar Heating for Hot Water. Other than space heating there is a substantial requirement for hot water for showers and toilet facilities. Given the extensive roof area of the new development, much of it facing due south, it would make long term sense to utilize some of that space for a system of solar panels to provide hot water for the development. At this stage of the design process, a detailed design has not been commissioned however there is ample panel space available to allow for an optimum solution, with appropriate levels of hot water storage. The existing gas boiler will be available for ‘top-up’ provision. 4.2 Space Heating 4.2.1 Consideration has been given to the use of heat pump technology. Initial investigations have suggested that the adjacent waterway would be a prime source of ‘free’ heat however this has been discounted at present due to: (a) Extra capital outlay and cost of consents associated with obtaining British Waterway approval and carrying out disruptive works within the towpath and to the waterway itself to make the necessary connections. (b) Costs associated with mitigating the chilling effect of the ‘used’ water and the need to extend works beyond the current site boundary. (c) On going charges from British Waterways for the continuing use of the waterway as a heat source. The long term energy supply for the building would be locked into a single supplier with no option for competitive pricing. 4.2.2 A possible alternative under consideration is to utilize ground source heat pumps linked to boreholes within the site boundary. The potential of such a system will be carried out at detailed design stage, assuming planning permission is granted. There is, however, significant flexibility in the design (depth) and number of boreholes required to provide sufficient heat. This would be linked to a system of under floor heating throughout the new buildings – the slightly lower operating temperatures being well suited to the main gym and bar areas. By employing this system the installation would be self contained without associated ongoing fees and charges to third parties, however this system is well down the list of sustainable options. Where practical the under floor heating would be extended into the existing building however existing construction may make this impractical in which case the existing gas heating would remain. 4.3 Photovoltaic Arrays 4.3.1 Subject to the final detailed design it may be viable to utilize photovoltaic arrays on part of the south facing roof slopes, for example, to power the heat pumps. This may well hinge on the incentives available at the time of construction and at present it remains a factor under consideration. A final decision on whether or not the financial outlay and ‘payback’ period can be justified would be taken during the detailed design phase of the development. At present it appears more likely that enhanced insulation and MVHR would be a more cost effective option. 4.4 Wind Turbines 4.4.1 Given the low lying and relatively sheltered location of the site, it is not considered likely that sufficient energy would be generated by any form of wind turbine that could be justified in terms of ‘payback’. It is suggested that this is the least likely form of renewable energy suited to this site and building. Windy conditions are not conducive to rowing activities so periods of peak generation would run counter to peak periods of demand. 4.5 Combined Heat and Power (CHP) 4.5.1 A further system to be fully evaluated is a combined heat and power engine to replace or run in tandem with the existing gas boiler. The potential of such a system will be carried out at detailed design stage, assuming (conditional) planning permission is granted. 5. Current Approach • • • • • The current design starts from a point of ‘fabric first’ and utilizing energy efficient fittings and appliances. A solar hot water system is to be employed to serve toilets and showers. Photovoltaic panels could be easily integrated into the roof of the development with minimal impact with final proposals linked to feed-in tariffs. An optimum system will be carried out during the detailed design stage. CHP will be given a detailed evaluation and costing when a planning permission is in place due to the further level of detailed design and associated cost required. This will need to be balanced against replacing the existing gas boiler. Heat pump options require a more detailed evaluation and costing which will be carried out when a planning permission is in place due to the further level of detailed design and associated cost required.