Gerald Spencer, P.E. has more than 50 years experience serving as the Engineer of Record responsible for the design and construction of the MEP portions of more than 1300 building construction projects since 1968 including more than 30 years of preparing forensic engineering reports. Gerald Spencer, P.E. has also been providing licensed professional engineering expert opinion and testimony concerning HVAC, electrical, plumbing, cryogenics, ventilation, construction contract compliance, construction cost  estimating, construction contract acquisition, construction contract administration, and other construction matters for attorneys with  since 2001.



REFRIGERATION SYSTEMS



GROCERY STORE AIR CONDITIONING AND REFRIGERATION:  Refrigeration systems used in food retailing today are changing to meet the requirements for energy efficiency and environmental concerns.  New installations are using new HFC refrigerant blends to replace the older CFC refrigerants -- R- 12 (medium temperature) and R-502(low temperature).  New medium temperature systems are using R-134a, and low temperature systems are using blends of two or more of the following: R-134a, R-125, R143a, and R-32.  The recommended blends available for low temperature at this time include three ternary blends and one binary blend -- R-407A, R-47013, R-507, and R-404A.  A compromise is to use R-22 for all temperatures, understanding that R-22 will be banned in 10 years.  R-22 would not be recommended for new, but where it is already existing in a good system, it should be considered as a part of a phase out program.

1.      Because the condensing temperatures of these new blends are typically higher than that of the older R-502 for air cooled systems, design pressures of system components and vessels has to be rated for 4OO psig in lieu of the 350 psig of R-502 systems.  For this reason, water cooled condensing becomes more economically feasible.  This opens up opportunities to integrate a common condensing water loop for air conditioning and refrigeration.  If the heat pump technology is used on the air conditioning, there are tremendous opportunities for complementary performance when the systems are linked in this manner.  This is an emerging concept that has great potential.

2.      For conversions of existing systems, the solutions are not easy.  There is no simple inexpensive process that will convert existing CFC and HCFC to the long-term alternatives.  Oil selection alone is a big problem, pipe sizing often is inadequate.  The number of system types, the ages of equipment, operating efficiency, and installation quality all vary.

3.     Air conditioning in a food retailing environment is critical.  It is imperative that humidity be controlled.  Without direct humidity control, refrigeration systems will cool the store, causing the air conditioning back off, causing humidity to zoom out of control.  For every IO% rise in relative humidity within the store, the load on cases increases 5 0%.  Additionally, coil frosting increases significantly, requiring defrost cycles, which are devastating to energy costs.

4.      To solve the humidity problem, there are several solutions'.

5      Use standard vapor compression systems with reheat.  Reheat may be gas, electric, or refrigeration reclaim.  This will work in dry climates.

6.    Use specialized vapor compression equipment with high latent coils, by-pass air arrangements, and reheat.  Reheat may be gas, electric, or refrigeration reclaim.  These systems are the majority of that employed in quality installations in humid climates.

7.     Desiccant dehumidification combined with vapor compression cooling.  These systems provide desiccant dehumidified air into cold isles and around cases.  These systems do an excellent job and are energy efficient, but there is a high first cost.

8.    Water cooled heat pumps.  May use a common condenser water loop with refrigeration systems.  Cooling, outside air pre-treating, and reheat, are all independently controlled and use the condenser water loop.

9.     The following is a list of refrigeration projects where SEI was the Refrigeration System EOR.

9.1.     U S Army - Fort Polk - Bldg 4366 Central Cold Storage Facility - ReplaceAll Refrigeration Systems 350 tons - Miscellaneous Repairs - $1,796,000

9.2.     M D Anderson Cancer Center - Smith Research Building - Add Cold Storage Rooms in various research labs.

9.3.     USPS Central Mail Facility - Repair Two 500 ton Centrifugal Chillers

9.4.     Safeway Grocery Stores No. 405, 406, & 409 - Houston, Texas

9.5.     Fort Hood, Texas - Three Post Exchange Buildings with Refrigerated Vegetable Storage, Dairy Product Storage, and Frozen Food Freezer.

9.6.     Lackland AFB - Enlisted Men's Dining Facility - Refrigerated Vegetable Storage, Dairy Product Storage, and Frozen Food Freezer.

9.7.     TRADE WINDS MOTOR HOTEL AND ADDITION - WICHITA FALLS, TEXAS - Motel with full restaurant plus refrigerated food storage.

9.8.     HOLIDAY INN PARK 10 - 19 FLOOR - 350 ROOMS - HOUSTON, TEXAS - MEP Consultant - This is a high rise hotel with restaurants, kitchen plusrefrigerated food storage.

9.9.     L'HOTEL SOFITEL - 8 FLOORS - 375 ROOMS - HOUSTON, TEXAS - MEP Consultant - This is a high rise hotel with three separate restaurants, meeting rooms, indoor swimming pool. laundry and two full kitchens plus refrigerated food storage.

9.10. ALBERT PICK HOTEL 250 ROOMS - 10 FLOORS MEMPHIS, TENNESSEE - MEP Consultant - We designed the HVAC, Electrical and Plumbing systems for this facility with a kitchen plus refrigerated food storage.

9.11. EXECUTIVE INN 150 ROOMS - 4 FLOORS - MEP Consultant - We designed the HVAC, Electrical and Plumbing systems for this facility with restaurant plus refrigerated food storage.

9.12. Exxon, USA - Production Research Facility Cafeteria -  - Refrigerated Vegetable Storage, Dairy Product Storage, and Frozen Food Freezer.

9.13. STEPHENVILLE HIGH SCHOOL - STEPHENVILLE, Texas - A one level (9th-12th grade) school that included, Kitchen and refrigerated food storage, etc. for 1000 students.  We designed the MEP for this project.