The ATMOsphere Review Board has announced its case study selection for presentation at ATMOsphere America 2015, which will take place on 25 & 26 June in Atlanta, Georgia. With a record- breaking 300 – 350 participants expected, the event will once again serve as a unique opportunity for HVAC&R professionals to share experiences and knowledge on all things related to natural refrigerants.
Hillphoneix, Carnot Refrigeration, Sanden, Bitzer US, KAV Consulting and Carter Synergy will take the stage to showcase their technology innovations using CO2 in commercial and industrial refrigeration applications, heat pumps and data centers.
Case study with a national retailer – comparing calculated energy consumption and actual energy results of a CO2 booster system by Jeff Newel, Hillphoenix
At the previous ATMOsphere America in June 2014, Hillphoenix presented the theoretical energy consumption of a CO2 booster system with an adiabatic gas cooler that was being installed at a Sprouts Farmers Market store in Dunwoody, Georgia. The case study explored the differences in energy consumption between that system and the standard DX R407a system typically installed in Sprouts stores.
This 2015 case study will draw comparisons between what was theoretically predicted for energy consumption at the store and what has been measured during operation. It will also discuss the practical side of doing in-store energy studies and obstacles that arise in the operation of any type of refrigeration system installed at a supermarket.
Aquilon is emerging at Bell Canada by Marc-André Lesmerises, Carnot Refrigeration
Telecommunication giant Bell Canada has teamed up with Carnot Refrigeration to remove HCFCs from its server rooms. The challenge was to develop the first CO2 transcritical refrigeration system for server rooms, which have very high standards of quality and reliability, as the data stored in these facilities is critically important. To meet this challenge, Carnot reinvented the refrigeration of server rooms by creating the first Aquilon system, for installation at one of Bell Canada’s server rooms in Ottawa.
The project involved replacing an R22 refrigeration system with a CO2 transcritical system of 105 kW, although the R22 system was kept operational during the installation of the Aquilon system. The Aquilon installation was a turnkey project in terms of electricity, refrigeration, structure, ducting, commissioning and also in obtaining permits and accreditations of TSSA (Technical Standards & Safety Authority).
Residential CO2 heat pump water heaters cold climate field-testing by John Miles, Sanden International USA
Sanden is currently collaborating with a consortium of utilities, government and university resources to conduct three different field tests across multiple sites in the North West of the U.S. These field tests are designed to assist in determining performance, efficiency, integration and product life cycle costs for a split type CO2 heat pump water heater product when used in multiple applications in a cold climate geographic area, including the use of the unit to provide both domestic hot water and space heating for a home. The Sanden split type CO2 units used are based on the Eco Cute water heater products currently sold in Japan with specific modifications for the North American Market.
The case study presentation details an analysis of the energy monitoring results together with observations about the operation of a split type CO2 based heat pump water heater installation during a field test. The results provide tangible data showing that a split type CO2 heat pump water heater offers significant sustainable efficiency improvements over existing North American water heater products. The presentation will also discuss some of the challenges related to the CO2 heat pump water heater, especially for a split product, where the CO2 heat pump is separate from the water tank.
An “Industrommercial” CO2 system by Joe Sanchez, BITZER US
As CO2 continues to gain in popularity, many users are finding that the high volumetric capacity of this refrigerant (i.e. smaller compressors) is leading to some additional flexibility in the uses of the compressors. For example, the industrial world has been using larger open drive industrial sized compressors for subcritical CO2. By using commercial sized compressors, they increase the part load efficiency; they employ semi-hermetic designs with less risk of shaft seal leakage and they decrease the effect of a down compressor. As, in many situations, ammonia is becoming a burden to apply in large quantities, expanding the usability of CO2 ensures that a natural refrigerant is employed as opposed to using an HFC refrigerant.
The case study presents one of the largest industrial sites in the U.S. to employ this style of compressors. So far, the only other industrial application of semi-hermetic CO2 compressors has been with ice rinks. If the customer has success with this concept, it could lead to many other applications employing a similar concept.
A desktop study into the energy efficiency and environmental benefits of CO2 refrigeration in USA supermarkets by Klaas Visser, KAV Consulting
This study shows that the specific electrical energy consumption per square foot of supermarket floor area would be reduced by 20 to 30% when using integrated multi function two stage transcritical CO2 refrigerating systems with parallel compression (MF2STTCCO2RSPC) employing hybrid evaporative condensers and gas coolers for CO2 condensing and gas cooling. These large projected reductions in energy consumption are due to the fact that the annual average COPs for MF2STTCCO2RSPC MT refrigeration is about 6, and about 2.5 for LT refrigeration, which are double and nearly double the R404A COPs of 3 and 1.5 for MT and LT refrigeration respectively. This would result in annual electrical energy cost savings of $47,000 to $70,000 at an electrical energy cost of $0.10/kWh.
Integrated CO2 convenience refrigeration installation by Paul Bevington, Carter Synergy
The purpose of this project was to bring CO2 refrigeration to the BP estate and ensure that the maximum value and benefit in terms of environmental impact were achieved. As the key supplier, Carter Synergy designed and provided a fully integrated refrigeration solution, which provided all refrigeration capacity, a second temperature band for air conditioning and all building heat through heat recovery. Following the installation in 2014, a period of monitoring in direct comparison with a store of the same format in Cockfosters was initiated and continues to date.
The study, carried out for 6 months so far, demonstrates a 45% reduction in energy use for the store refrigeration and HVAC services, which ensures that the payback on investment will provide significant benefits to BP across the life cycle of the equipment. The monitoring provides an excellent snapshot as it covers months with both high ambient temperatures and very low temperatures. Based on this data the expectation is that these savings will continue. The case study will look at how the project can be replicated in North America and present additional solutions for warm climate states.
To read the full abstracts for the case studies listed above, as well as for case studies selected for other applications, please have a look at the following articles: