Consideration was given to either replace or repair chiller and was based on available technology and cost. The Trane model E reciprocating compressor had been a source of problems over the years with multiple internal design changes for oil return, compressor cooling, oil sump level control and oil equalization from compressor suction chambers to oil sump and motor compartment to oil sump. Countless moving parts cause vibration due to counter balanced rotating parts, coupled with piston and connecting rod throws which promote vibration and noise and were transmitted through duct work, annoying tenants.

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.

Understanding that earlier vintage reciprocating compressor chillers used return chilled water as a control point and at 100 % load your coldest chilled water would be achieved. When the chiller reached design temperatures the compressor would unload and the leaving chilled water temperature would rise. The air handling systems discharge air temperature would rise which explains the building dehumidification problem. Building discharge air temperature oscillated with unit leaving chilled water temperature!

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. reworked the cooler section to control on leaving chilled water and installed two Sporlan electronic expansion valves which operate in parallel. The old control scheme staged the TXV' s by cycling liquid line solenoids. The Sporlan EXV 50's are 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 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:

1. Integrated oil separator
2. Liquid injection rotor housing
3. Liquid injection into motor housing
4. Vapor injection
5. External oil cooling ports
6. Discharge service valve
7. Discharge check valve
8. Suction service valve
9. Infinite loading from 25% of compressor capacity
10. Step loading and unloading (0%-33.3%-66.6%-100%) Additional SOL Required
11. Oil float
12. Motor temperature control
13. 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 standard!

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