Improving the energy efficiency of dehumidification technology at a large facility in Florida

Abstract

This thesis examines energy use and management of twenty heat pipes used in dehumidification systems at a large (10,000+ acre) facility in Florida. Eleven of the twenty heat pipes use electric strip heaters that, when activated, consume 693.8 kW of electrical power from the grid. Solar photovoltaics, specifically a silicon monocrystalline ceil with 22.5% efficiency, were considered as a means to provide an alternative energy source and opportunity for cost savings for 11 of the heat pipes (Sunpower, 2011). The remaining nine heat pipes use hot water heaters for which alternative energy sources were not considered. Data gathered and analyzed include weather, solar irradiance, PV size and cost, utility incentives, emissions, fuel consumption, energy cost, and heat pipe operating parameters. These data were used to calculate the (1) annual electricity cost for the heaters, (2) installed cost for enough PV to offset electric heater energy use, (3) surface area needed to install the estimated PV system, (4) one-time and ongoing financial incentives, (5) avoided energy savings, (6) avoided fuel usage and emissions, and (7) the undiscounted payback period of the various equipment investments. Savings were calculated to be almost $600,000 annually (approximately $145,000 attributable to the heaters) if PV were to power the heaters 125 days of the year and ancillary systems at other times. The cost of an appropriately sized PV system (4.57 acres with between 8,553 and 15,205 PV panels depending on panel size) was estimated at $3,228,806 assuming $150,000 of electric utility incentives. It was also estimated that the photovoltaic (PV) system could earn $85,087 in annual tax credits through the Florida Renewable Energy Production Tax Credit program, and that the undiscounted payback period would be about five years. Further, the use of728,350 US gallons of oil, and the emission of 13,656.6 lbs of S02, 9,104.37 lbs ofNOx, and 10,843,300 lbs ofC02, could also be avoided. It is recommended that the installation of PV energy generation capabilities be further investigated. It is also recommended that further research be performed to obtain accurate costs and benefits of integrating solar thermal into the hot water heaters at the facility because of the complexity of integrating solar thermal into the existing hot water heaters, the lack of readily available price information regarding solar thermal heating, and the fact that the hot water heaters consume about $170,000 per year.