Tips and Rules for Handling Hydrocarbons safely
27 January 2010
The first significant increase occurred about five years ago when Unilever changed to R290 in its point of sale ice cream freezers. The second shift is a rapid rise in the use of HC refrigerants in the UK over the last year due to the move to natural refrigerants by most retailers in their new systems. For the majority this switch has primarily been to R744 (carbon dioxide), with HC refrigerants used:
- As a high stage refrigerant in some R744 cascade systems;
- As the refrigerant in chillers which remove heat from systems using R744 as a pumped volatile secondary fluid;
- In small integral systems such as ice makers, commercial fridges and some display cabinets.
However, one major UK retailer - Waitrose - has moved totally to HC refrigerants in its new stores and major refits. So far eight stores utilise hydrocarbon refrigerant in all the refrigeration and air conditioning systems. The installations comprise integral cabinets and close coupled cold room systems. Most of these are water cooled, using chillers which utilise free cooling for much of the year. Typically these systems cool up to 50 cabinets.
All the systems are factory assembled, processed and charged and are virtually leak free. Typically the total on site HC charge is less than 100 kg, with an individual maximum charge of 10 kg in the chillers outside and less than 1kg individual maximum charge inside the building.
This has virtually eliminated the direct RAC system impact on climate change through the elimination of HFC refrigerant coupled with almost zero leakage. Stores using traditional central plant refrigeration typically have an entrained charge of 750 kg of R404A. They leak at an average rate of 15% a year, i.e. approximately 112.5 kg / year. Experience to date shows the HC systems have a negligible leak rate.
The store’s HVAC system benefits from utilising waste heat and cold air spillage from the refrigeration systems. This integration of refrigeration and HVAC significantly reduces the store’s carbon footprint and its running costs.
The capital cost of the new systems is currently cost neutral although in the longer term it is expected that this first cost will reduce. As well as the 77.5% carbon savings, there are also benefits associated with reduced install time, 40% reduction in service and maintenance costs, good energy efficiency and flexibility in the event of store layout changes.
The new concept for refrigeration and HVAC is now standard for all new Waitrose stores and all major refits. All stores will use this concept within 10 years.
Cool Concerns has worked with Waitrose and its equipment suppliers to ensure all HC systems meet the relevant standards. This has included determining the potential flammable zones around systems and the specification of electrical devices and enclosures. Cool Concerns has also trained store staff so they are aware of the reasons for using HC refrigerants and the additional safety procedures.
Cool Concerns also provides training for engineers who will be servicing and maintaining HC equipment, and have seen a sizeable increase in the number of engineers requiring this training over the last few years. Unlike HFC refrigerants, there is no legal requirement for engineers to be qualified to handle HCs. However, the major supplier of HC refrigerant in the UK (BOC) has a sales policy, which limits the sales of these refrigerant to engineers who have attended the training session.
In addition, standard EN378-4:2008 (Refrigerating systems and heat pumps, safety and environmental requirements) specifies that anyone repairing equipment using flammable refrigerants should be trained to achieve competence in safety aspects of HC refrigerant handling. This includes:
- Knowledge of relevant regulations, standards and legislation;
- Knowledge and skill in handling HC refrigerant, personal protective equipment, leak prevention, cylinder handling, charging, leak detection, recovery and disposal.
More about Cool Concerns
Cool Concerns Ltd provides practical consultancy and training for the commercial refrigeration and air conditioning sector. The company is owned and run by Jane Gartshore and Stephen Benton - both experienced refrigeration engineers. We have worked on a wide range of hydrocarbon related activities since the mid 1990s. This includes developing and presenting training on the safe use of hydrocarbon refrigerant to engineers worldwide, and working with end users and equipment manufacturers to ensure HCs are appropriately and safely applied.