A new remote refrigeration system from Master-Bilt features a modular system design that is said to save energy and reduce in-room heat and noise.

The MRS series modular multi-compressor refrigeration system from Master-Bilt (New Albany, MS, U.S.) combines the multiple refrigeration systems from commercial applications (i.e., walk-in freezers, refrigerators, and chillers) found in restaurants, hotels, and foodservice operations, and condenses them into a single system with individual modules and compressors. Additionally, the company says the customized modular design helps the system protect itself from failure while automatically lowering energy costs by reducing room temperature with its remote installation.

A producer of full-line commercial refrigeration systems for several years, Master-Bilt says it achieved this by making the refrigeration components modular. Instead of using a single-slab compressor that divides the tube between the total number of compressors, the MRS series keeps all condenser coils separate from one another in modules. Besides a condenser and compressor, each module contains a receiver, dryer, sight glass, and dual pressure controls, and are housed in a 304 stainless-steel frame.

According to the company, each module includes a compressor that is connected to an individual condenser. Kenny Owen, engineering manager for Master-Bilt, says that by using four different frame sizes for the unit, any combination of compressors can be configured to fit the respective frame, which ultimately allows for a custom and efficient refrigeration system with the capability to fit up to 14 modules.

'Our multi-circuit racks include all of the same components as a typical refrigeration system, and they work exactly the same,' Mr. Owen tells APPLIANCE. 'The huge benefit of our rack is that we use modular condensers. If a [traditional] multi-circuit condenser fails, all systems have to be shut down to replace the condenser. If there is a problem in a MRS rack condenser, only the module with the problem has to be replaced, and the other system can run normally.'

The remote MRS system can be roof- or ground-mounted and this, the company says, helps to lower air-conditioning load, and thus costs, because it takes the heat out of the kitchen--literally. According to Mr. Owen, the remote system eliminates the need to compensate for the condenser heat with the air-conditioning system, and the user is then using less energy to cool the room. As an added benefit, noise is also reduced due to the remote installation. Mr. Owen says roof-mounted systems are the most popular, as they save on real estate by using overhead space instead of ground space.

In addition, the unit features an optional electronic controller system called the Master Controller. According to Mr. Owen, the controller replaces the need for an expansion valve, timer, thermostat, defrost termination, and thermometer, and increases the systems reliability against failure. 'By eliminating these parts that commonly fail with electronic and electromechanical parts, the total system reliability goes up,' Mr. Owen explains.

The optional control system also reduces energy consumption. This is achieved in two ways, according to Mr. Owen. First, the controller system utilizes an intelligent defrost scheme that allows it to defrost itself only as it is required, unlike traditional systems that use defrost cycles. Secondly, the control system uses an oversized electronic expansion valve that eliminates the need for a head pressure control device. 'By eliminating the head pressure control device, the condensing temperature is allowed to go lower in lower ambient conditions,' Mr. Owen says. 'Compressors operate at much higher energy efficiency rates at lower condensing temperatures, and the total savings can be over 25 percent in cold climates.'

The control system also features a reverse-cycle defrost system, which is still awaiting patent approval. For walk-in cooler or freezer applications, this system utilizes an added valve on the condensing unit. The valve reverses high-temperature refrigerant back through the evaporator coil so that it heats the entire coil during defrost cycles and eliminates frost build-up.

The company says that with all the features combined, the MRS is a cost-effective and efficient appliance. 'We already build many racks for large-volume customers, but we wanted to design a system so that we could offer one-of-a-kind, custom racks in a cost-effective manner,' Mr. Owen says. 'By using four different sizes of housing and making the refrigeration components modular, we accomplished this.'
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