DA-00-01-2 -- Comparing Maintenance Costs of Geothermal Heat Pump Systems with Other HVAC Systems: Preventive Maintenance Actions and Total Maintenance Costs PDF

Total annual heating, ventilating, and air-conditioning (HVAC) maintenance costs were determined for 20 schools in the Lincoln, Nebraska, Public School District. Each school examined provides cooling to over 70% of its total floor area and relies on one of the following heating and cooling systems to provide the majority of space conditioning: vertical-bore, geothermal heat pumps (GHPs), air-cooled chiller with gas-fired hot water boiler (ACC/GHWB), water-cooled chiller with gas-fired hot water boiler (WCC/GHWB), or water-cooled chiller with gas-fired steam boiler (WCC/GSB). A precursor to this study examined annual costs associated with repair, service, and corrective maintenance activities tracked in a work order database. This follow-up study examines costs associated with preventive maintenance (PM) activities conducted by the district. Annual PM costs were 5.87 ¢/ yr·ft² (63.14 ¢/yr·m² ) for ACC/GHWB schools, followed by 7.14 ¢/yr·ft² (76.86 ¢/yr·m² ) for GHP, 9.82 ¢/yr·ft² (105.39 ¢/yr·m² ) for WCC/GSB, and 12.65 ¢/yr·ft² (136.30 ¢/yr·m² ) for WCC/GHWB. The results of the two analyses are combined to produce an estimate of total annual maintenance costs, by system type, for the 20 schools. Total annual maintenance costs were 8.75 ¢/yr·ft² (94.20 ¢/ yr·m² ) for ACC/GHWB schools, followed by 9.27 ¢/yr·ft² (99.76 ¢/yr·m² ) for GHP, 13.54 ¢/yr·ft² (145.49 ¢/yr·m² ) for WCC/GSB, and 18.71 ¢/yr·ft² (201.61 ¢/yr·m² ) for WCC/GHWB. It should be noted that these costs represent only the trends seen in the maintenance database of the Lincoln School District. Because of differences in the number of schools using each system type, varying equipment age, and the small total number of schools included in the study, the maintenance costs presented here may not be representative of the maintenance costs seen for similar equipment in other locations.

Units: Dual