High Performing Buildings - Fall 2009 - (Page 32)

figure 2 1 . 5 t o n Pa r t i a l c o m P r e s s o r t e m P e r at u r e Both stages 360 psi/110°F condenser Capacity (Btu/h) Power (W) Current (Amps) mass flow (lb/h) 142 psi/50°f evaporator stage 1 only 157 psi/55°f evaporator 29,488 1,608 7.1 378.9 18.34 67.7 e n e r g y at a g l a n c e energy use intensity (site) 26.8 kBtu/ft2 electricity 26.8 kBtu/ft2 Annual source energy 89.51 kBtu/ft2 Annual energy Cost index (eCi) $0.87/ft2 · yr energY sTAr rating 99 energy efficiency ratio (Btu/W · h) efficiency (%) 475 psi/130°F condenser Capacity (Btu/h) Power (W) Current (Amps) mass flow (lb/h) energy efficiency ratio (Btu/W · h) efficiency (%) note: These are reciprocating compressors that use r-410A. Building enVeloPe roof 1 20,330 1,868 8.2 296.1 10.88 66.4 Type standing seam metal with 3 in. rigid insulation on metal decking overall r-value r-22 reflectivity 30.3, sri 31 roof 2 Type single-ply membrane, 3 in. rigid insulation, metal decking overall r-value r-24.85 reflectivity 85, sri 108 elimination of large central equipment such as boilers, chillers and cooling towers. this reduces maintenance costs in addition to improving efficiency. Distributed pumping eliminated the last remnants of central plant equipment—the main recirculating water pumps and the associated speed control system. WCpS previously tried various geothermal pumping systems. these included constant flow/single pump, variable flow/single pump and primary/secondary pumping with variable flow. the performance of the variable flow system was not successful in reducing the water flow of the central recirculating pumps to match loads. Cmta and WCpS worked together on plano elementary to eliminate the central pumps and associated variable-frequency drive units, 32 HigH Performing attempting a new pumping concept. each heat pump unit has an individual water pump to recirculate the water through the entire geothermal water loop, including the well field. the water pump will not operate unless its respective heat pump unit is in operation. this ensures variable water flow, which only responds to demand. the closed loop piping system was designed to minimize the water pressure drop in the geothermal piping system. previous projects had a typical loop pressure drop of 75 ft total developed head (tDH), while plano’s loop pressure drop was 35 ft tDH. the “installed” total horsepower of pumping capacity was reduced by half compared to the district’s previous school. most pipe mains in the building were increased one pipe size to fa l l 2 0 0 9 Walls Type Brick, 1.5 in. insulation, 8 or 12 in. concrete masonry unit (Cmu) overall r-value 11.6 (average between 8 and 12 in. Cmu assembly) glazing percentage 8% (43,327 ft2 of wall, 3,841 ft2 of glazing/storefront) Basement/Foundation slab edge insulation r-value: r-6 (horizontal and vertical insulation) Windows u-value 0.41 solar Heat gain Coefficient (sHgC) 0.66 Visual Transmittance 49% location latitude 36° 53' 13.34" n orientation east/West Buildings

Table of Contents for the Digital Edition of High Performing Buildings - Fall 2009

High Performing Buildings - Fall 2009
Contents
Commentary
Kitsap County Administration Building
McDonald's Corporation
Plano Elementary School
California Department of Education
Burns & McDonnell
Advertisers Index

High Performing Buildings - Fall 2009