IPWG agenda 120700 - Laserfiche WebLink

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174 1 . All thermal components can be quantitatively improved . For example , Volume X , ACP Table IV ( for Orange County ) requires a maximum Root U value of 0 . 068 . A compliant roof design for this project would have a U value that is 30 % less than this Table IV value or : 0 . 068x ( 1 . 0 - 0 . 3 ) - 0 . 0476 . Using this method , the upgraded values for envelope compliance are listed below . ACP 30 % Component Table IV Improved Roof U value 0 . 068 0 . 048 Wall U value 0 . 121 0 . 085 ( For all walls . Higher U values allowed for mass walls ) Slab R value 7 . 0 9 . 1 (24 inches vertical ) 2 . Volume X limits the amount of glass area (Window Wall ratio ) for aquatics buildings from 14 to 48 % , based on the' amount of window overhang , glazing shading coefficient, and window U value . Once the maximum Table IV value is established , the Town ordinance value will be 30 % less . Volume X allows extra glass area . for buildings that install qualifying daylighting systems (See daylighting section below) . 3 . An alternate compliance method would allow the designer to use energy code tradeoff compliance s software ( ENVSTD or COMCheck ) to demonstrate thermal compliance . Trade -off methods , which are authorized by the U . S . Department of Energy, allow designers more flexibility in designing buildings . In an aquatic facility example , higher levels of wall insulation in the natatorium could be traded off against allowing more window area in the dry side of the facility. The proposed method to use a trade off compliance in conjunction with the Town ordinance would be as follows . The designer would establish a baseline total heat transmission value ( Ua Total ) for the building using the proposed envelope surfaces areas multiplied by the appropriate values listed in ACP Table IV . Then the designer would re-calculate the total envelope condition using the proposed design thermal values . The design would comply with the Town ordinance when the building Ua Total value of the proposed components is 30 % less than the baseline value . - - 41 Where there are limits on efficiency improvements , such as fuel-fired heating system and . motor efficiencies , the 30 % multiplication will require a modification . Take for example an energy efficient motor. For a 25 Horsepower, 2-Pole motor, Volume X requires a minimum efficiency of 89 . 5% , whereas .the maximum efficiency fo'r the required motor may be 95 % . Increasing 89 . 5 % by 30 % 4 results . 10 11 6 . 35% 9 which is an impossible requirement to achieve since motor efficiencies must be less than 100 % . The prcpmed method to demonstrate compliance in this case follows . The Town ordinance efficiency value is determined I by the minimum Volume X value plus 30 % of the difference between the minimum value and what is the highest value availableAn1he ' marketplace . An example of this would be a gas boiler with an available efficiency range of 80 to 96 % . In this case , the 30 % improved value would be : _ . . ': 80 %• + 903 * (96-80)%- 84 . 8 % . . ' . t' . 5 . Where quantifiable improvement$•• are not * possible in significant energy conservation areas , the . 60 designer should propose a number of qualitative efficiency improvements to comply with the intent of Town ordinance . A good example of this case would be pool covers. Volume X requires a pool cover on all pools ( unless 70 % of pool water . heating is provided by solar heating ) . By minimizing surface water evaporation , pool covers are one of .the. largest energy , saving , features for swimming pools (if they are used on a daily basis ) : The qualitative improvement here would be to install . semi or automatic . covers instead of manual cover0 . s . Manually rolling in and . out the , large covers required for big commercial 4pools is •often strenuous work . Daily cover use by the . pool operators w il' I ' be ° far more' likely 4 if this process is substantially accomplished at the push of a - button .'