I ~ I REFRIGERATION RETROFIT

mart u e'em

to c 00 Ohio University saves tens of thousands of dollars

on retrofit projects by allowing its facilities man­

agement team to do the jobs instead of contracting

out for the work. The head of the team explains

how they did it By Bryan Sherman

5

The medium-temperature end of the refrigeration rack at Nelson Commons Is shown.

Joe Proffit of KAL Electric (left) and Ohio University's Bryan Sherman check two of the medium-temperature compressors for the refrigeration rack at Nelson Commons Dining Hall. .

28 RSES Journal - February 1998

he facilities management division at Ohio University (OU) recently proved there's truth in the old saying that if you want it done right, do it

yourself. By planning and conduct­ing the retrofit of refrigeration sys­tems at two dining halls on the school's campus they not only got it done right, but saved the school plenty of money at the same time.

The department employs 21 peo­ple who maintain more than 5,000 pieces of equipment. Though we're always shorthanded, we pride our­selves on working smarter instead of harder. The design/build team con­sisted of Steve Andrews, Phil Frash, Jim Rodehaver, Mike Beard, Cecil Coconougher, Bob Dehmann, Mike Daugherty, Bryant Facemyer, CM, and myself. All are RSES members.

Ohio University usually contracts out large retrofit projects like the ones we did. That thinking changed, however, after the facilities manage­ment division's involvement with a retrofit of the Baker Center, which is located in the university's student union. We fought hard with an out­side contractor to get the type of system that would work best at the center.

At Baker Center, we ended up using a Larkin brand dual-refriger­ant rack. While it is a good system, it's not what we originally wanted and cost more money. The system we preferred was a single-refriger­ant, dual-temperature rack, which we used for another campus project involving Nelson Dining Hall.

Because of the success of our sys­tem recommendations and the repairs we made to correct installa­tion errors done by the original con­tractor, the food services director at OU gave us the opportunity to work on two more retrofit projects.

The next project was a retrofit of the refrigeration system at Shively Dining Hall. Built in 1956, Shively Hall contained once-through water cooled condensing units which were

A new condenser sits on the roof of Nelson Commons at Ohio University.

converted to air-cooled units over the years. The original refrigeration systems consisted of dairy, meat and vegetable refrigerators, and a small freezer. Sometime later a larger freezer was added to the back of the building. All of the condensing units were located in a small room, which is now used for dry goods storage.

Shively Hall required an increased freezer and dry goods stor­age area. Funding wasn't available, however, to replace the walk-in freezer. Making matters worse, all of the refrigeration equipment was old and operated on CFCs. Before we began any work on Baker Center we had studied 32 new refrigerants on the market to determine their cost, efficiency, longevity, range 0f appli­cation, oil required and retrofit needs. This helped us with the other retrofit projects.

Because of the amount of hvacr equipment on campus we wanted to limit the number of refrigerants and oils used. We have become accus­tomed to dealing with five primary refrigerants and one specialty (low­temp cascade system) refrigerant, including R-11, R-12, R-22, R-502, R-718 and R-503. Keeping this in mind, we waited as long as we could to see how the market and the expe­rience of others would shake out.

Developing a strategy In the interim we addressed each system on an individual basis with an appropriate solution in mind. We used R-507 in our low-tempera­ture equipment. On existing medi­um-temperature equipment we use R-409A until we are able to replace the older equipment.

We brought panels from some of the old freezers from Baker Center to the university's air conditioning and refrigeration shop to fabricate panels to make an extension to the Shively freezer that sits outside the facility. The extension required removing one of the end walls that held up the roof. The aclr perspnnel wrapped 4-by-4s with stainless steel and built a support beam. They also fabricated panels, adding 4 feet to the freezer.

Next we had to analyze our inventory of used evaporators and condensing units. We had one sys­tem that had alkylbenzene oil and the necessary displacement and horsepower to provide cooling to the new 220-square-foot walk-in cooler, which uses R-409A. We found two units with the displacement and horsepower to operate the freezers with R-507, which requires POE oil. We ran out the mineral oil and checked it with our refractometer until it was correct.

February 1998 - RSES Journal 29

I ~ I REFRIGERATION RETROFIT

mart u e'em

to c 00 Ohio University saves tens of thousands of dollars

on retrofit projects by allowing its facilities man­

agement team to do the jobs instead of contracting

out for the work. The head of the team explains

how they did it By Bryan Sherman

5

The medium-temperature end of the refrigeration rack at Nelson Commons Is shown.

Joe Proffit of KAL Electric (left) and Ohio University's Bryan Sherman check two of the medium-temperature compressors for the refrigeration rack at Nelson Commons Dining Hall. .

28 RSES Journal - February 1998

he facilities management division at Ohio University (OU) recently proved there's truth in the old saying that if you want it done right, do it

yourself. By planning and conduct­ing the retrofit of refrigeration sys­tems at two dining halls on the school's campus they not only got it done right, but saved the school plenty of money at the same time.

The department employs 21 peo­ple who maintain more than 5,000 pieces of equipment. Though we're always shorthanded, we pride our­selves on working smarter instead of harder. The design/build team con­sisted of Steve Andrews, Phil Frash, Jim Rodehaver, Mike Beard, Cecil Coconougher, Bob Dehmann, Mike Daugherty, Bryant Facemyer, CM, and myself. All are RSES members.

Ohio University usually contracts out large retrofit projects like the ones we did. That thinking changed, however, after the facilities manage­ment division's involvement with a retrofit of the Baker Center, which is located in the university's student union. We fought hard with an out­side contractor to get the type of system that would work best at the center.

At Baker Center, we ended up using a Larkin brand dual-refriger­ant rack. While it is a good system, it's not what we originally wanted and cost more money. The system we preferred was a single-refriger­ant, dual-temperature rack, which we used for another campus project involving Nelson Dining Hall.

Because of the success of our sys­tem recommendations and the repairs we made to correct installa­tion errors done by the original con­tractor, the food services director at OU gave us the opportunity to work on two more retrofit projects.

The next project was a retrofit of the refrigeration system at Shively Dining Hall. Built in 1956, Shively Hall contained once-through water cooled condensing units which were

A new condenser sits on the roof of Nelson Commons at Ohio University.

converted to air-cooled units over the years. The original refrigeration systems consisted of dairy, meat and vegetable refrigerators, and a small freezer. Sometime later a larger freezer was added to the back of the building. All of the condensing units were located in a small room, which is now used for dry goods storage.

Shively Hall required an increased freezer and dry goods stor­age area. Funding wasn't available, however, to replace the walk-in freezer. Making matters worse, all of the refrigeration equipment was old and operated on CFCs. Before we began any work on Baker Center we had studied 32 new refrigerants on the market to determine their cost, efficiency, longevity, range 0f appli­cation, oil required and retrofit needs. This helped us with the other retrofit projects.

Because of the amount of hvacr equipment on campus we wanted to limit the number of refrigerants and oils used. We have become accus­tomed to dealing with five primary refrigerants and one specialty (low­temp cascade system) refrigerant, including R-11, R-12, R-22, R-502, R-718 and R-503. Keeping this in mind, we waited as long as we could to see how the market and the expe­rience of others would shake out.

Developing a strategy In the interim we addressed each system on an individual basis with an appropriate solution in mind. We used R-507 in our low-tempera­ture equipment. On existing medi­um-temperature equipment we use R-409A until we are able to replace the older equipment.

We brought panels from some of the old freezers from Baker Center to the university's air conditioning and refrigeration shop to fabricate panels to make an extension to the Shively freezer that sits outside the facility. The extension required removing one of the end walls that held up the roof. The aclr perspnnel wrapped 4-by-4s with stainless steel and built a support beam. They also fabricated panels, adding 4 feet to the freezer.

Next we had to analyze our inventory of used evaporators and condensing units. We had one sys­tem that had alkylbenzene oil and the necessary displacement and horsepower to provide cooling to the new 220-square-foot walk-in cooler, which uses R-409A. We found two units with the displacement and horsepower to operate the freezers with R-507, which requires POE oil. We ran out the mineral oil and checked it with our refractometer until it was correct.

February 1998 - RSES Journal 29

III I

All of the units we had were indoor units so we had to modify them to run at outdoor ambient temperatures, which can go below zero. This required adding a crank­case heater, flooded head pressure controls and fan cycling switches to the system. The school's tunnel maintenance shop built us a bracket to hang the condensing units on the wall above the freezer and the sheet metal shop made a roof to keep the weather out. The boxes were fitted with new lights and U.S. Depart­ment of Agriculture-required clean­able surfaces.

Shively Dining Hall now has all new refrigeration with only a small investment in pipes, valves, fittings and controls. It has more cooler space, more freezer space, a new dry goods storage area where the condensing units previously were located, and a new door on the old freezer that maintains -10' F.

An engineering firm's projected cost for this retrofit without increasing capacity was $72,000. We did the project for less than $10,000. Our work earned us the respect and confidence to bid

specialist at Heatcraft, for some ideas. Without hesitation or any prompting, Williams suggested using a single refrigerant rack with two suction headers and a common discharge.

We presented all of the data on the boxes, existing equipment and current product loads. Heatcraft performed calculations with their software, and we did some calcula­tions using Elite Software. After comparing the numbers, we found some discrepancies that we adjusted for. Most of these differences and adjustments revolved around prod­uct load. We were able to base our figures on numbers presented by the food service department. Heatcraft wasn't able to base their calculations

on the next project, which was Nelson Commons.

An estimated 4,000 meals are served daily in Nelson Commons, Ohio University's biggest dining

The piping and controls In the produce cooler show the sensor, pumlHfown switch, back·up thermostat, solenoid with manual stem, ball valves with Integral pressure ports, dryer and sight glass.

hall. An engineering firm said it would cost from $157,805 to $194,860 for replacement of the major equipment. This included a -30' F blast freezer, a -10' F storage freezer, a 45" F thawing room, three push-throughs (units that contain doors at the kitchen side and at the serving line), and 34' F coolers for milk, produce, cheese and hot food storage. The firm based its budget on exact replacements of these units.

Another consultant presented a $230,000 estimate, which didn't include the push-throughs. Past experience told us we could do the job better and for less money. We put in a $150,000 bid on the entire project. In addition, we contacted Dean Williams, custom refrigeration

30 RSES Journal - February 1998

on those figures so they used indus­try standards.

We also had to deal with fixed box sizes, which limited coil sizing. As a result, we had to look at every detail, like the compressor run times, delta T and product pull­down times. Williams designed the rack and remote air-cooled con­denser/receiver package. We asked him to use the same controller used at Baker Center, which included CPC's UltraSite refrigeration moni­tor and case controller and Sporlan Valve's suction filter housings and flooded head pressure controls.

The project was then turned over to the ac/r shop to do a layout. Facemyer volunteered to be lead technician and the rest joined in

for what was a team effort. I did the pipe-sizing calculations to make sure there was adequate velocity with minimal pressure drop. As it turned out, we needed to run a double discharge riser.

Meanwhile, Andrews, Beard and Facemyer started to layout the pipe runs and verified placement and component fit. This turned out to be an issue when two of the coils would not fit in their boxes. We had fun trying to fit different coils in the blast freezer. One coil had good capacity, and it would have worked except it wouldn't go through the door. We ended up sacrificing some capacity to find one that fit.

Heatcraft built the six-compres­sor, single-refrigerant rack to our

standards using Copeland's "D" model semi-hermetic compres­sors. The system was designed and installed, with no expenses spared, for $125,000, including a complete inventory of spare parts. The system could last 1 00 years.

One of the nice things about OU is that the talent and ability of the craftsmen is unmatched. If we can't buy it, we can make it. The hvacr shop motto is "We can fix anything but a broken heart."

Inside the system The unit fired up with no errors.

The refrigeration rack uses three medium-temperature and three low-temperature compressors with a separate suction header for each temperature. The low-temperature header has an EPR valve on the -10' F box. There is over 1,500 feet of conduit, which we subcontracted out to KAL Electric.

We ran more than 750 feet of copper, including the double dis­charge riser, without one leak. Every component in the system is isolated with a full port refrigeration ball valve and has pressure ports to enable our technicians to plot the system on a PH diagram, which we mounted on the rack.

The microprocessor-based control is backed up 100 percent

I

r I

One of the three condensing units in use at Shively Dining Hall uses R-409A.

by electromechanical controls. Each evaporator has a dryer, sight glass, ~-inch schrader valves, full port ball valves on the inlet and outlet, and a permanently mounted thermistor at the bulb of the externally equalized, balanced port TXV.

The medium-temperature equip­ment uses off-cycle defrost and the fans run constantly. The low-tem­perature coils have electric defrost with temperature and time termina­tion. There are separate disconnect switches mounted in each box for fans and heaters. Each box has an "old reliable" Penn temperature con­trol mounted on the wall, which is wired in parallel with the liquid line solenoid and a pump down switch both in the box and at the rack.

The air-cooled condenser/receiv­er on the roof uses fan cycling and flooded condenser controls for head pressure. Alco Controls fan cycling switches are wired in parallel with microprocessor outputs, which are adjusted just out of range. There is a dryer and sight glass on the outlet of the receiver with a bypass ar­rangement so the dryer cores can be changed on line. Finally, there is a king valve, as well as a couple of schraders and ball valves so that each component can be checked or isolated.

The rack has Alco's electrome­chanical, low-pressure, oil-pressure and high-pressure switches all wired in series with the microprocessor and adjusted just out of the operat­ing range. The low-temperature compressor group has head cooling

fans because of the high-compres­sion ratio.

The compressors were sized so that each one handles between 40 and 50 percent of the load. That way if we lose a compressor we can ship parts and pieces if we don't already have them in stock and take the time to establish the cause rather then treating the symptom.

The controller evens out the run times of the compressors. In addi­tion, a modem is hooked into the controller that allows any OU tech­nician to troubleshoot from home or call it to download trends. If trouble occurs at any time, the con­troller calls our on-call pager and notifies the technician on duty right away. The alarms include low refrigerant, low pressure for each group, and high/low oil pressure.

Our team laid out the system and every component in it and it has everything any technician could want. The control panel has a lami­nated T and P chart for R-507 and a laminated copy of the PH diagram with the system plotted and a table with all the conditions listed.

We had enough money left over to buy a complete set of dryers, and extra relay boards, transducers, tem­perature sensors, solenoid coils, valve plates, gaskets, refrigerant and oil. We sprayed the tops of all the walk-ins with 1- to 2-inch spray foam and topped that with a nonper­meable coating. We also refitted all the walk-in doors and replaced eight ofthe 12 doors on the push­throughs.

We received the coils the first week of December, though some of the boxes had to be kept operating---­until after a wedding on Dec. 14. The condenser/receiver was deliv-ered on Dec. 7 and tied in and pres-surized by the following Monday. The whole team worked overtime, and when the rack arrived one week later they really went to town on it.

Up and running When Rusty Walker from Heatcraft came to start up the system on Dec. 19, he was amazed. He thought he would be going home and coming back to start it in another week. He couldn't believe that the equipment could be shipped and ready to start within a week.

We had 350 psi on the system in little more than a day. Later the sec­ond day, Beard and Coconougher started the vacuum pumps. They were able to pull a vacuum, purge with nitrogen while installing the cores, and isolate the system in four places while running four, eight cfm pumps until it was dry (-30' F dew point). Two days later, Facemyer and Rodehaver broke the vacuum and dumped 450 pounds of R-507 into the receiver.

After Walker got over the shock of us being ready, he asked to see the rest of system. (I think he still thought something was wrong.) We followed the discharge line to the condenser and when we reached the first evaporator, Walker told me it was the most well thought-out sys­tem he ever saw.

The moral of the story is that it can pay to do the job yourself when you have talented people working with you. We did it more efficiently and for less money than the engi­neering and contracting firms were able to offer. The recognition we received from Heatcraft for a job well done was the bonus .•

Bryan Sherman, an RSES member, is the associate director of engineering services at Ohio University in Athens, Ohio.

February 1998 - RSES Journal 31

III I

All of the units we had were indoor units so we had to modify them to run at outdoor ambient temperatures, which can go below zero. This required adding a crank­case heater, flooded head pressure controls and fan cycling switches to the system. The school's tunnel maintenance shop built us a bracket to hang the condensing units on the wall above the freezer and the sheet metal shop made a roof to keep the weather out. The boxes were fitted with new lights and U.S. Depart­ment of Agriculture-required clean­able surfaces.

Shively Dining Hall now has all new refrigeration with only a small investment in pipes, valves, fittings and controls. It has more cooler space, more freezer space, a new dry goods storage area where the condensing units previously were located, and a new door on the old freezer that maintains -10' F.

An engineering firm's projected cost for this retrofit without increasing capacity was $72,000. We did the project for less than $10,000. Our work earned us the respect and confidence to bid

specialist at Heatcraft, for some ideas. Without hesitation or any prompting, Williams suggested using a single refrigerant rack with two suction headers and a common discharge.

We presented all of the data on the boxes, existing equipment and current product loads. Heatcraft performed calculations with their software, and we did some calcula­tions using Elite Software. After comparing the numbers, we found some discrepancies that we adjusted for. Most of these differences and adjustments revolved around prod­uct load. We were able to base our figures on numbers presented by the food service department. Heatcraft wasn't able to base their calculations

on the next project, which was Nelson Commons.

An estimated 4,000 meals are served daily in Nelson Commons, Ohio University's biggest dining

The piping and controls In the produce cooler show the sensor, pumlHfown switch, back·up thermostat, solenoid with manual stem, ball valves with Integral pressure ports, dryer and sight glass.

hall. An engineering firm said it would cost from $157,805 to $194,860 for replacement of the major equipment. This included a -30' F blast freezer, a -10' F storage freezer, a 45" F thawing room, three push-throughs (units that contain doors at the kitchen side and at the serving line), and 34' F coolers for milk, produce, cheese and hot food storage. The firm based its budget on exact replacements of these units.

Another consultant presented a $230,000 estimate, which didn't include the push-throughs. Past experience told us we could do the job better and for less money. We put in a $150,000 bid on the entire project. In addition, we contacted Dean Williams, custom refrigeration

30 RSES Journal - February 1998

on those figures so they used indus­try standards.

We also had to deal with fixed box sizes, which limited coil sizing. As a result, we had to look at every detail, like the compressor run times, delta T and product pull­down times. Williams designed the rack and remote air-cooled con­denser/receiver package. We asked him to use the same controller used at Baker Center, which included CPC's UltraSite refrigeration moni­tor and case controller and Sporlan Valve's suction filter housings and flooded head pressure controls.

The project was then turned over to the ac/r shop to do a layout. Facemyer volunteered to be lead technician and the rest joined in

for what was a team effort. I did the pipe-sizing calculations to make sure there was adequate velocity with minimal pressure drop. As it turned out, we needed to run a double discharge riser.

Meanwhile, Andrews, Beard and Facemyer started to layout the pipe runs and verified placement and component fit. This turned out to be an issue when two of the coils would not fit in their boxes. We had fun trying to fit different coils in the blast freezer. One coil had good capacity, and it would have worked except it wouldn't go through the door. We ended up sacrificing some capacity to find one that fit.

Heatcraft built the six-compres­sor, single-refrigerant rack to our

standards using Copeland's "D" model semi-hermetic compres­sors. The system was designed and installed, with no expenses spared, for $125,000, including a complete inventory of spare parts. The system could last 1 00 years.

One of the nice things about OU is that the talent and ability of the craftsmen is unmatched. If we can't buy it, we can make it. The hvacr shop motto is "We can fix anything but a broken heart."

Inside the system The unit fired up with no errors.

The refrigeration rack uses three medium-temperature and three low-temperature compressors with a separate suction header for each temperature. The low-temperature header has an EPR valve on the -10' F box. There is over 1,500 feet of conduit, which we subcontracted out to KAL Electric.

We ran more than 750 feet of copper, including the double dis­charge riser, without one leak. Every component in the system is isolated with a full port refrigeration ball valve and has pressure ports to enable our technicians to plot the system on a PH diagram, which we mounted on the rack.

The microprocessor-based control is backed up 100 percent

I

r I

One of the three condensing units in use at Shively Dining Hall uses R-409A.

by electromechanical controls. Each evaporator has a dryer, sight glass, ~-inch schrader valves, full port ball valves on the inlet and outlet, and a permanently mounted thermistor at the bulb of the externally equalized, balanced port TXV.

The medium-temperature equip­ment uses off-cycle defrost and the fans run constantly. The low-tem­perature coils have electric defrost with temperature and time termina­tion. There are separate disconnect switches mounted in each box for fans and heaters. Each box has an "old reliable" Penn temperature con­trol mounted on the wall, which is wired in parallel with the liquid line solenoid and a pump down switch both in the box and at the rack.

The air-cooled condenser/receiv­er on the roof uses fan cycling and flooded condenser controls for head pressure. Alco Controls fan cycling switches are wired in parallel with microprocessor outputs, which are adjusted just out of range. There is a dryer and sight glass on the outlet of the receiver with a bypass ar­rangement so the dryer cores can be changed on line. Finally, there is a king valve, as well as a couple of schraders and ball valves so that each component can be checked or isolated.

The rack has Alco's electrome­chanical, low-pressure, oil-pressure and high-pressure switches all wired in series with the microprocessor and adjusted just out of the operat­ing range. The low-temperature compressor group has head cooling

fans because of the high-compres­sion ratio.

The compressors were sized so that each one handles between 40 and 50 percent of the load. That way if we lose a compressor we can ship parts and pieces if we don't already have them in stock and take the time to establish the cause rather then treating the symptom.

The controller evens out the run times of the compressors. In addi­tion, a modem is hooked into the controller that allows any OU tech­nician to troubleshoot from home or call it to download trends. If trouble occurs at any time, the con­troller calls our on-call pager and notifies the technician on duty right away. The alarms include low refrigerant, low pressure for each group, and high/low oil pressure.

Our team laid out the system and every component in it and it has everything any technician could want. The control panel has a lami­nated T and P chart for R-507 and a laminated copy of the PH diagram with the system plotted and a table with all the conditions listed.

We had enough money left over to buy a complete set of dryers, and extra relay boards, transducers, tem­perature sensors, solenoid coils, valve plates, gaskets, refrigerant and oil. We sprayed the tops of all the walk-ins with 1- to 2-inch spray foam and topped that with a nonper­meable coating. We also refitted all the walk-in doors and replaced eight ofthe 12 doors on the push­throughs.

We received the coils the first week of December, though some of the boxes had to be kept operating---­until after a wedding on Dec. 14. The condenser/receiver was deliv-ered on Dec. 7 and tied in and pres-surized by the following Monday. The whole team worked overtime, and when the rack arrived one week later they really went to town on it.

Up and running When Rusty Walker from Heatcraft came to start up the system on Dec. 19, he was amazed. He thought he would be going home and coming back to start it in another week. He couldn't believe that the equipment could be shipped and ready to start within a week.

We had 350 psi on the system in little more than a day. Later the sec­ond day, Beard and Coconougher started the vacuum pumps. They were able to pull a vacuum, purge with nitrogen while installing the cores, and isolate the system in four places while running four, eight cfm pumps until it was dry (-30' F dew point). Two days later, Facemyer and Rodehaver broke the vacuum and dumped 450 pounds of R-507 into the receiver.

After Walker got over the shock of us being ready, he asked to see the rest of system. (I think he still thought something was wrong.) We followed the discharge line to the condenser and when we reached the first evaporator, Walker told me it was the most well thought-out sys­tem he ever saw.

The moral of the story is that it can pay to do the job yourself when you have talented people working with you. We did it more efficiently and for less money than the engi­neering and contracting firms were able to offer. The recognition we received from Heatcraft for a job well done was the bonus .•

Bryan Sherman, an RSES member, is the associate director of engineering services at Ohio University in Athens, Ohio.

February 1998 - RSES Journal 31