PCX150-OHRQ

DUNHAM-BUSH PCX150-OHRQ

APPLETON, WISCONSIN

RC SERIES SCREW RETROFIT

The focus of this project was to replace an existing DUNHAM-BUSH compressor model 1613DHF2LOD with a Hanbell RC16 hermetic compressor, add micro processor control and electronic expansion valve, and re-design the external oil circuit. By doing so would eliminate an external open drive oil pump and an open drive compressor with carbon shaft seals . Most important the customer wanted to reduce maintenance and energy cost!

The original design of this process chiller was to supply all demand process chilled water requirements 12 months a year. Natural gas was not available to heat buildings in the early 70's so excess heat from the system's single bundled condenser could be routed to fan coils to heat the plant or train dock space. Summer cooling loads were 120 ton while winter loads were 105 ton. The cooler was designed to provide a constant 37 deg F glycol and water brine to the process equipment which was raised to 45 deg F. when the plant went to only water in the chilled water loop. Condenser load for summer is 85 deg F. entering and 95 deg F leaving and on a reset schedule below 58 deg F outdoor air condenser design reset from 95 deg F to110 deg F. leaving at ) deg F OAT.

All associated equipment was assessed. The condenser and chilled water pumps were in proper working order and replacement parts are still available. The compressor motor starter was a Y-Delta Closed Transition Reduced Voltage starter which could be designed to handle the reduced power requirement of a new RC Series compressor. The existing system capacity was more than enough to handle the current cooling requirements. The chillers electromechanical controls and the electronic temperature load controls were out dated and would require a MCS Microprocessor upgrade.

SAMSA, Inc. identified all operational and system design problems which would require attention in order to improve system reliability and performance.

Unit location and cost to replace entire chiller was weighed against an existing system retrofit, upgrading the unit in tune with today's technical advancements while using the vessels that were in place. The system condenser and cooler sections were in great shape with little corrosion.

SAMSA, Inc. engineered a system retrofit which would use what is used today from the old chiller and adapt to the older unit what is new technology of today.

SAMSA, Inc. installed one Sporlan electronic expansion valve to replace two Alco Pilot Operated Expansion Valves which are obsolete. The old control scheme staged the TXV' s by cycling the POS solenoids. The Sporlan EXV 100 is controlled by a new MCS-8 microprocessor which senses leaving chilled water and compressor suction superheat. Based on the suction superheat set point, design chilled water set point and infinite compressor loading and unloading above 25 % compressor capacity, controls leaving chilled water +- 0.5 deg. F.

The Micro Controls MCS-8 micro processor was the ticket to up grade the out dated electrical mechanical control scheme to a new level of control. The power of electronics and the versatility was without question one huge step from the past, right into the future. The ease of integration and our ability to program all points, set limits and configure the micro was without question a product that pushed this retrofit past what was being offered from any other OEM.

The MCS-8 facilitates all operational control. All chiller pressures and temperatures are monitored, calculated suction, discharge superheats, liquid sub cooling, coupled with entering and leaving cooler and condenser water temperatures adjusts compressor load constantly. Remote monitoring is a breeze with dynamic updating via an internet IP address from anywhere in the world. Now what company is offering that?

Let's talk about Compressors. We have discussed some of the modern attributes of retrofitting an older system, bring what some see as obsolete machinery to today's sophisticated and technically advanced units. Compressors have advanced in screw compression also. What was once only available in 150 tons and up is now available from 30 tons and up to 600 tons, but not all screw compressors are alike.

SAMSA, Inc. uses the Hanbell RC Screw Compressor. The list of standard option is unmatched in the industry. Standard warranty is two years. If the compressor is controlled by a Micro Controls, Inc. MCS-8 or MCS Magnum controller an additional one year compressor warranty is included. That's right, a three year compressor warranty at no additional charge. You can't beat that anywhere!

Compressor standard options include:

Integrated oil separator
Liquid injection rotor housing
Liquid injection into motor housing
Vapor injection
External oil cooling ports
Discharge service valve
Discharge check valve
Suction service valve
Infinite loading from 25% of compressor capacity
Step loading and unloading (0%-33.3%-66.6%-100%) Additional SOL Required
Oil float
Motor temperature control
High discharge temperature sensor

SAMSA, Inc. provided the engineering for this project from start to finish. Start up and warranty service on the new compressor and associated parts were also furnished. All other component manufacturers supplied one year parts warranty on their equipment.

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Consider this before you toss out the old for new:

This "SAMSA, Inc RC Series Screw Retrofit" was less than half the cost of a chiller replacement, with three times the compressor warranty and a part load energy savings of over $ 14,000.00 per year!

SAMSA, Inc. is a must for your next project where innovative ideas are paramount.

What are you waiting for?