生物燃料,重新设计

Leave it to a simple but big-dreaming farmer in Lancaster County, Pa., to help create a giant shift in the agricultural and heating industries worldwide.

You want sustainable? Chicken farmer Earl Ray Zimmerman will give you sustainability but you’ll have to climb a mountain of nutrient-rich debris to get it. And that was the genesis of the project at Zimmerman’s chicken farm in 2012.

In Pennsylvania, poultry is the state’s biggest business. And that means giant piles of bird waste. Typically, farmers truck it to fields. But that creates a lot of work and surface runoff. While Zimmerman was exploring his options, a local energy-solutions company was putting the pieces together for a heating system plan to take the need for heat and the need to dispose of manure — and cancel them both out.

Today, Zimmerman is quick to smile and eagerly talks about the heating system that materialized from that plan. Last winter, his two, 500-ft.-long chicken houses were entirely heated with the use of a state-of-the-art, bio-fueled hydronic system retrofit.

The long, low poultry houses are each equipped to organically raise 30,000 broilers (chickens for meat), from peeps to slaughter weight in just five to seven weeks. The breed of chicken is specifically selected for maximum growth in minimal time. Such rapid growth requires an exorbitant amount of chicken feed. What goes in must come out; therein lies the first of numerous challenges solved by the Zimmerman’s manure-fired, hydronic retrofit.

Win-Win … Win

“鸡粪——或垃圾,因为它是已知的agriculture sector — is a relatively low-energy, solid-state fuel,” says Matt Aungst, co-owner of Total Energy Solutions in Willow Street, Pa., the company behind the entire design of the heating system. “You’re looking at roughly 3,500 BTUs per pound, compared to coal with a gross heating value of 13,000 BTUs per pound. But, unlike coal, there’s a never-ending supply of chicken ‘fuel’ at the Zimmerman farm. If there’s a call for heat, there will always be litter.

“We’ve taken the needs of the modern poultry farmer, combined with biofuel combustion technology and — with this installation — dramatically multiplied the benefits by perfecting the heat distribution via custom controls and fan-coil technology not yet seen in the U.S. poultry industry.”

The result can be seen in significant cost reduction and production increases for the farmer, energy independence, reduction of water-source pollution, health and living condition improvement for the animals and more.

成立于2004年,当时盟总能源解决方案ngst and co-owner John Albright brought together a common desire to provide energy-saving options for heating and lighting systems. One of their focuses is the agricultural industry.

“For this project, we teamed up with two companies who lead their markets in craftsmanship and ingenuity,” Aungst notes. “Farmer Boy Ag Supply, in Myerstown, Pa., was our general contractor and provided installation talent, and Taco Inc., in Cranston, R.I., provided the engineering brainpower to get the BTUs where they need to be with the KV series sensorless pumps.”

Depending on the outdoor temperature and the age of the birds, one house can call for up to 600 MBH at any given time, but an average heat load in the winter is likely to be around 200 to 300 MBH per house. The center of the hydronic system is a 1.5 million BTU boiler. The system was designed and engineered by Total Energy to provide 100 percent of the heat load at any given time of the year.

One of the most obvious benefits of a litter-burning boiler is that the fuel needs to be disposed of. But, if you ask Zimmerman, getting rid of litter was the least of his needs.

Sustainable Heat

When a flock of birds “goes out” every six weeks, Zimmerman uses a skid-loader to clean all the litter out of the chicken house, storing it until it’s needed. At that point, he dumps the dry material into a hopper near the mechanical shed.

The boiler — a Blue Flame Stoker — is the size of a service van and occupies its own remote building, erected several hundred feet from the chicken houses. An auger feeds dry manure from the hopper into the boiler, while another auger removes the ash remnant from the bottom of the firebox. The boiler doesn’t produce strong odors or much smoke. While it does release some emissions during the process, the effect is negligible when compared to the potential run-off and water pollution had the manure been spread on fields.

The heart of the distribution system also is in the mechanical building. Unlike residential hydronic systems — with pipe going in many directions and manifolds full of zone valves — the near-boiler piping appears minimalistic. Two redundant green pumps and their VFD counterparts sit side by side, plumbed in parallel. Three-inch diameter, pre-insulated Logstor PEX water lines disappear underground through a hole in the clean concrete floor. From there, they run 300 ft. to a distribution manifold between the two chicken houses.

Suspended 10 feet above, a Taco 4903 air-and-dirt separator keeps the water lines clean and quiet. On the slab, a 125-gal. Taco expansion tank smooths the loop out. No antifreeze is used or needed.

“Paul Silvestre at B.J. Terroni was instrumental in helping us with this project,” Aungst says. “He assisted us with expansion tank and air separator selection and put us in touch with engineers at Taco.” Bensalem, Pa.-based B.J. Terroni is a stocking manufacturer’s rep firm.

“I’ve been using Taco’s HSS software for more than six years now,” he says. “I used the program to design every facet of the distribution system at Zimmerman’s.” The free HSS (hydronic systems solutions) software allows engineers to calculate loads, size equipment and compare different systems.

Hi-Tech, Down on The Farm

The new Taco SKV3009 SelfSensing pumps each include a motor-mounted variable-frequency drive to deliver the precise amount of flow and pressure needed for the two chicken houses. The pumps accurately respond to changes in system demand without the need for pressure sensors. If Aungst closes a main supply valve to one of the houses, the pump senses the change and ramps down according to the lower demand. Seconds later, the pressure gauge on the supply side starts to drop.

Inside each chicken house, eight CUBO unit-heaters hang from the ceiling, providing the water-to-air heat exchange. The units are designed exclusively for the poultry industry and provide air mixing, destratification and lateral heat distribution in a full 360 degrees.

Each one of these unit heaters has its own Danfoss pressure independent control valve (PICV). These valves act as variable-zone valves with the ability to modulate flow — as opposed to simply opening or closing. These will function automatically, depending on the temperature at the nearest thermistor, or Zimmerman can operate each manually via any web-enabled device. The valves, similar to the rest of the controls system, are low-voltage, reducing installation cost.

However, the PICVs need a compatible circulation system. The pumps react to the specific call for water, regardless of the number of valves calling or how far open the valves are. The modulation of the valves provides a more consistent load on the pumps and the boiler when compared to valves that are simply open or closed — which is especially important for a biofuel system.

“Before the SKV3009 SelfSensing pumps were shipped, the VFDs were programmed in our Cranston factory, according to data collected for specific flow rates, head pressures and system characteristics,” notes Eugene Fina, senior product manager at Taco, who was involved with the design of the inline pump portion of the distribution system.

“A specific program enables the pumps to ‘know’ exactly what speed to run at any given time,” Aungst adds. “You get tremendous energy savings this way.” When in the design phase, he calculated for a delta-T of 25 F.

Additionally, the system is equipped with a color touchscreen control system designed, engineered and programmed by Total Energy Solutions. This unit automatically controls each zone independently via PID (proportional-integral-derivative) control loops and is connected via Ethernet to enable Zimmerman to monitor his houses remotely.

Accuracy is Paramount

The 7.5 horsepower pumps are each programmed to supply a maximum of 125 gal./minute at 85 ft. of head. Jeff Pitcairn, Taco’s commercial regional manager, says pump A runs as “duty,” leaving pump B for backup. After 84 hours of run-time (roughly half a week), the pumps automatically switch roles.

To cut down on space and clutter in the mechanical room, the distribution piping incorporates Taco's Plus Two multipurpose valves, which combine all the valve functions normally required on the discharge side of a centrifugal pump into a single unit. This includes shut-off, check, balancing and flow metering valves.

Chickens are extremely temperature sensitive, Zimmerman says. In a chicken house, even a 10-degree drop for an hour could seriously affect his bottom line. Temperature fluctuation would affect feeding habits for the day. If birds stop eating, they stop growing. If 30,000 birds lose even one day of growth on a six-week schedule, it could mean thousands of dollars lost for the farmer.

There’s little doubt Zimmerman’s installation achieves energy savings, heat distribution and farm production benefits that surpass any other hydronic poultry heating system available.

By design, the CUBO units hang down the center of each house to draw air from the ceiling level, passing it through a water-to-air coil where it’s ejected at an adjustable height close to the floor. As the birds grow, the units are raised to supply heat at the optimal level for bird growth.

The hydronic system serving Zimmerman’s chicken houses is so accurate that the eight thermistors — spread evenly across each 22,500-sq.-ft. house — all read within one degree of each other. Having the ability to tightly control house climate allows Zimmerman to increase what farmers call the “feed conversion” — a calculation of how efficiently a bird converts feed into meat.

Since Zimmerman gets paid by the pound of bird, the ability to raise his feed conversion is by far the largest benefit he sees from retrofitting his facilities. Although the boiler eliminates fuel costs, without the ability for the Taco pumps to deliver the precise amount of water needed, Zimmerman wouldn’t be much better off than he was with his original heating system. Temperature control in a chicken house is of utmost importance.

But the advantages of an accurate hydronic system don’t end there for chicken farmers.

Typically, farmers heat chicken houses by direct gas-fired units. Direct combustion inside the house uses oxygen and produces substantial humidity — both of which force the farmer to run ventilation fans for the health of the birds, even in the dead of winter.

Fan motors can use a lot of energy but, more importantly, the ventilation process greatly raises the heat load. A dryer house also means lower ammonia levels, a byproduct of manure, heat and moisture. “It’s just one more benefit to the mountain of advantages we’ve found on this job,” Aungst says.

Zimmerman is an early-adopter. The roof of one of the chicken houses is adorned with a 72 kW photovoltaic array and he has protected a nearby stream from runoff by growing a riparian buffer zone. Recently, he replaced his CFL lights — nearly 100 per house — with high-efficiency LED bulbs.

At a time when food prices are hiking nationally, smarter agriculture systems can produce more food with less cost and lower environmental impact. That’s smart farming.