The home heating oil industry has a long and proud history, and Fuel Oil News has been there supporting it since 1935. It is an industry that has faced many challenges during that time. In its 77th year, Fuel Oil News is doing more than just holding
Issue link: https://read.dmtmag.com/i/270766
P oultry and livestock products are big business in Pennsylvania, responsible for $4.5 billion in annual agricultural sales. Organic poultry farmer Earl Ray Zimmerman is adding to that number, thanks to a heating system using Danfoss AB-QM pressure independent temperature control and system balancing valves to maintain the precise temperatures chickens need to keep gaining weight to go to market as fast as possible. "Chickens are affected by temperature," observed Matt Aungst, co-owner of Total Energy Solutions, a Willow Street, Penn.-based firm that engineered the heating system. "A change of just a few degrees affects the birds' eating habits. And if they don't eat, they don't put on weight. Missing the growth sched- ule for thousands of birds for just one day stretches a farmer's time to market and cash flow, something poultry producers want to avoid at all costs." Precise temperature balancing is critical in each of the 45 x 500-foot houses Zimmerman uses for broilers – chickens specifically raised for meat production. "Each building is wide open," Aungst said. "So each area has a different heat loss profile depending on the location in the building. The goal is to keep the entire building at 93 degrees Fahrenheit at the beginning of every flock." To hit that goal, Aungst and his partner John Albright offer an air handler designed specifically for chicken houses. Called the CUBO series air mixer, the system uses a centrifugal fan to circulate air through the mixer's coil into the chicken house to maintain even temperature throughout the living area. Each building employs eight CUBO units suspended from the ceil- ing. A heating coil in each unit is supplied by a hot water circuit regulated by its own Danfoss AB-QM valve. "The AB-QM valve is a pressure independent control valve that provides just the right flow of hot water to satisfy tempera- ture requirements exactly, which is ideal for our system," said Aungst. On warm days, the CUBO mixer pulls hot air from the ceil- ing level and expels it in a 360-degree circular flow just above the floor to eliminate stratification. On cold days, a boiler supplies hot water to the internal heat exchanger inside each CUBO unit. The system engineered by Total Energy Solutions uses an unusual fuel source — dried chicken waste — to fire the 1.5 million BTU boiler, which can handle 100 percent of the heat load. "The water flow to each coil is based on the heat load," explained Aungst. "At full load, the system supplies 180 degree F water at 11 gallons per minute to each CUBO unit. But condi- tions seldom call for that much heat." Eight AB-QM valves are located along the main piping circuit that runs near the peak of the roof in each building. One valve is used to control the water flow to one coil. The valve increases or reduces the flow of hot water supplied to the coil depending on whether the zone temperature sensors call for more or less heat. Because 100% flow is usually not needed, a Danfoss variable frequency drive incorporated into the circu- lating pump motor can reduce pump speed as flow is reduced, which cuts electricity consumption. However, changing the flow also changes pressures, which creates problems for the system. Aungst realized that alternatives to the AB-QM valves PICV design — traditional temperature control valves along with manual balancing valves — would not provide sufficient stability or controllability at low loads. According to William Boss of Danfoss Heating Solutions North America, who worked with Aungst to determine the best solution, "manual balancing valves don't work with vari- able-flow systems. They are meant for constant flow systems designed for maximum heat load using fixed-speed pumps, which in the CUBO application is the wrong choice." "But traditional temperature control valves used with man- ual balancing valves adjust to changing flow only after a change 44 march 2014 | FUEL OIL NEWS | www.fueloilnews.com HVAC/ HYDRONICS Case Study Danfoss AB-QM Valves in a Biofuel Heating System