In an expansion project creating an extra section for its new subsidiary company, the horticulturalist has added four CHP units; two for each greenhouse location. The electricity generated by these units, which run on natural gas, is amongst other sources used to light the site’s greenhouses. Meanwhile, the heat produced goes into a system that provides optimum growing temperatures.
“These aren’t exactly small units,” is Merford account manager Ben Vernie’s description of the machines. Featuring a gas-fired reciprocating engine and a generator, each can generate around 6 megawatts. They were manufactured by Bergen Engines, part of the famous Rolls Royce company, a valued connection of Merford going back over 10 years. “We basically placed a soundproof box on top of each of the units, thus reducing the operating noise to an acceptable level,” Vernie explains. “This is a maximum of 70 decibels for the sound attenuated mechanical ventilation system, which allows the CHP units to perform optimally and protect them from overheating, and a limit of 75 decibels at one metre distance from the housing.”
Acting as the grower’s turnkey supplier, Merford was entrusted with the task of overcoming construction challenges arising from the project’s size and the wet subsoil of its valley location. Showing great faith in Merford’s abilities, Bergen Engines extended its order beyond supplying the typical components of the four large housings. The additional elements included supply and assembly of safety access measures and service platforms to make the maintenance mechanics’ work easier. Merford also installed an electrical overhead crane to help in moving heavy machine components.
Housings of the kind supplied are never exactly standard products, and this was especially true here as the business owner opted for Bergen Engines’ smaller 6.5 MW CHP plants. “For the larger Bergen Engines CHP units of approx 8 to 10 MW we can rely on our extensive experience from previous projects,” Vernie explains. To accommodate the nursery’s power units, Merford had to design a new type of housing that fit this installation’s requirements.
“Bespoke projects are our speciality,” Vernie says. For this project, Merford set up a 3D design based on their own engineering activities in the field of noise, mechanical strength and air flow optimisation. The design of the ventilation system needed particular attention. Ventilation is required in the housing to ensure that gas engines and their accompanying machinery operate properly. Merford’s engineers designed a mechanical overpressure ventilation system that optimises temperatures inside the housing, thus allowing the engine to perform at optimum efficiency.
Merford prepares all components of its housings at its own premises. The various items are then delivered to the client in a flat packed kit form and assembled onsite by Merford’s own assembly crew. Prefabrication allows for swift assembly and minimises the amount of work and tailoring onsite. “For the access measures and service platforms we collaborated closely with our sub-suppliers,” Vernie notes.
At a basic level Merford’s housings consist of panels and doors made from plain and perforated steel sheets, with a rock wool infill. A carefully engineered combination of materials ensures the desired level of noise reduction and maintains it over time. Merford’s panels will remain in good working condition for the technological lifespan of the installation, preventing any leaks that would allow machine noise to escape. Vernie comments: “These properties contribute to Merford’s low-maintenance solutions.”
The net result of Merford’s work has been smooth project completion and an effective, long-term noise-limiting solution which keeps the local environment as peaceful as it was before the expansion.