Heat Recovery
AWARD AGC Build Wisconsin Award, 2012
CLIENT Kohler Company, Kohler, Wisconsin – Pottery and Brass Plants
GOAL To use recovered heat from kiln exhaust to heat water for sink showers and process applications and to heat the air used by the pottery ware driers.
OVERVIEW The Rohde team fully engineered and installed a high pressure closed hot water loop and thermal storage system with tight control integration that enables Kohler to recover and store heat for use at optimal times.
KEY PROJECT POINTS
- Kiln waste exhaust is 800-1000ºF
- Domestic water, approximately 18,000 gallons daily; is needed at 120ºF
- Product driers use heat at 250ºF
- Heat recovery controls needed to interface with Kohler’s Allen Bradley control system and the pottery drier control system, also Allen Bradley.
- The engineering to implementation timeframe was approximately one year, with a three-day plant shut-down for tie-ins.
DESIGN FEATURES
- Using 3-D modeling and FEA, Rohde determined that the high pressure hot water loop would need to accommodate 4” of thermal expansion.
- Rohde designed a custom thermal storage tank capable of holding 4,000 gallons of water at 400 PSIG. Typical storage systems run to 125 PSIG.
- Pump skid included pre-piped pumps, pre-wired pumps and a pre-wired control system with all censors
- Designed a web-based Honeywell control system to provide GUI for the Allen-Bradley system
SYSTEM PERFORMANCE
- Enables Kohler heat recovery of 254,000 therms per year. In the first year it saved $178,000 in natural gas costs.
- With 50% of project cost funding provided by Wisconsin Focus on Energy, the payback period is only 2.5 years.
- Remote monitoring and trending diagnostics contribute to greater efficiencies in production scheduling, and energy savings which significantly exceed projections.
CONTACT the Rohde Engineering team to discuss your heat recovery goals:
Mike Rohde, President, RohdeM@RohdeBros.com
Craig Bahr, Senior Engineer / Sales, BahrC@RohdeBros.com
