CHP unit: Farmpower

[cschuerm]

1: This is a system in preliminary design stage for a close friend.   The friends farm has a natural gas well and he has virtually unlimited "free" well gas available.  Location is NE Oklahoma, USA.

2: Eventual system goal is to provide all heat, cooling, and power to the farm house and large shop building 24/7.

3: The prime mover will be a modern oilfield engine (Fairbanks 118, Arrow) for reliability and supportability.  The engine will drive a DC generator (watching development of options on this site) to maintain charge of a battery bank.

4: System control will be via off-the-shelf industrial PLC equipment.  The engine will be automatically started/stopped as necessary to maintain battery charge.  Our intention at this time is to mechanically couple a freon compressor to provide air conditioning for the house.  We will be fabricating a heat exchanger to harvest waste heat during engine run and will experiment in an in-ground insulated tank for storage.  The basic system logic will be based on a tiered "on-demand" operation.  Sources of demand will be: electricity to charge batteries, cooling circuit, and heat.  Since we have gas available for a furnace, the heat call logic will utilize the engine as a secondary source rather than primary.
Once question yet to be answered is whether the well gas flow is sufficient for continuous engine operation.  We may have to add a compressor to pressurize the gas into a storage container.  Details TBD.

5: development stage at this time is in the design of the system and evaluation of components.  Due to the availability of the gas well, this project is worth putting a significant budget together to execute at a very high quality level.  Site prep work to build the house/shop has just begun and this cogen system will be an integral part of the overall build.  The owner is a master engine builder and custom fabricator with a complete machine shop, so we expect to move forward with prototype components by the end of the year with another year of iterative fine-tuning.

6: lacking any artistic creativity, we're just calling this unit "Farmpower" for now. :-)