2007_1015_Packet - Laserfiche WebLink

Home

Roseville Skating Center and City Hall Feasibility Study September 23,2007 operating and maintenance costs, since local refrigeration technicians can maintain the modular chillers, and scheduled compressor maintenance is not required. The use of a GHX in place of a cooling tower also reduces maintenance costs, as the operation of a GHX entails only the use of a circulation pump, and the underground piping is not exposed to the elements. (Note: in systems with a large thermal imbalance an evaporative fluid cooler may be required to prevent thermal saturation of the ground, but the equipment can be smaller because of the thermal storage capacity of the earth) It is estimated that maintenance costs in these facilities is 40% to 60% lower than that of a conventional systems. This is similar to the maintenance cost savings for geothermal systems indicated in several utility and industry association reports. The American Society of Heating, Refrigeration and Air Conditioning Engineers (ASHRAE) has reported that the expected lifespan of geothermal heating and cooling equipment such as that proposed for the refrigeration system and HVAC system in the Ice Arena / Banquet Hall can be expected to be 18 to 20 years. One of the main factors is that roof mounted heating and cooling equipment is exposed to the elements and is underthe greatest stress during extremeweather, preciselywhen it is required the most. Simple Payback There is an estimated cost difference of approximately$421,000 between the converting the current direct expansion system to a system with a secondary refrigerant, and the cost of installing a completely integrated geothermal system in the Ice Arena / Banquet Hall. There is an estimated reduction in electrical consumption on the ice arena of approximately $4,700 per year because of the reduced pumping cost for the ice arena, and an estimated reduction in gas consumption of approximately $18,700 annually, for a total energy cost saving in this facility of approximately 18 years. Note that this comparison is not completely "apples to apples", since the additional cost of replacing the Banquet Hall HVAC system is included, as is a significant portion of the GHX that can be expanded to incorporate the Maintenance Garage, the City Hall / Public Safety Building, the Fire Hall and the Speed Skating Oval. It is possible to proceed in stages on this type of project, and to replace equipment based on the longevity of the existing systems to help reduce the impact on the facility operating budgets. Geo-Xergy Systems Page 26 of 33