Our project is an Influent Pump Station (IPS) that is part of a larger sewage treatment facility. The building includes spaces that are conditioned to 45 degrees for heating and 80 to 95 degrees for cooling and are occupied only during maintenance and repair. We intend to model this building for both EAc1 and EAc2, and seek confirmation that our proposed modeling strategies are appropriate, or clarification how they should be modified. 1. The project utilizes hot water generated from bio-gas methane for heating, and cool plant effluent water for cooling. We propose to subtract the pump energy and odor control fans as process loads, but to include primary ventilation, heating and cooling of the spaces in the energy analysis. Please confirm whether this is the appropriate approach. 2. The Digester Complex is approximately 150 feet from the IPS and is a part of the same sewage treatment plant. The Digester Complex hot water loop is heated by boilers burning methane gas that is a waste product of the sludge digestion process. Currently, the loop serves to heat the Digester Complex and the digester tanks. Any excess gas is flared. The scope of work of our project includes making modifications at the Digester Complex to increase the heating capacity of the hot water system for our use at the IPS. This will include tapping into the existing hot water loop, and potentially piping in more waste gas from another building to increase the capacity. As we are turning a greenhouse gas waste product into an energy source that offsets the use of grid energy, we propose that this meets the intent of EAc2. Please confirm.
The proposed approach of subtracting the pump energy and odor control fans as process loads is acceptable as long as pump energy for circulating hot water or chilled water for space heating or cooling is included. Energy used for process loads should be subtracted from the models for budget and proposed buildings. Because the building will have intermittent occupancy, note that the schedules in the budget building and proposed building models should be identical EAc2 is intended to recognize renewable energy technology for on-site electricity generation. The energy savings from burning the waste gas to heat water is accounted for in EAc1 only. For the purpose of this analysis, it should be noted that comparison should be to natural gas, not electricity as fuel switching is not allowed in ASHRAE 90.1-1999. Applicable internationally.