Section 01 Alternatives to HCFCs in the Refrigeration and Air Conditioning Sector 36 Th e process of changing a refrigerant should in theory be an easy operation, but in a reality the situation is more complex because the alternatives to ODS developed for new systems require a different type of oil. This report uses the term “retrofit” to describe the process of changing refrigerant and oil; it uses the term “conversion to non-HCFC” to describe the change of service blends that do not require oil change. The retrofit of an old system is a challenging task in many respects, since the status of the old system is often unknown from the start and the new refrigerant as well as the oil has different properties. Equipment owners consider replacing the refrigerant for different reasons. The policies of the equipment owner as well as his/her economic situation often play a major role when it comes to the evaluation of the available options. The owners often decide to change the refrigerant in a system for the following reasons: An urgent need to do major repairs of the system, which ■■makes a conversion at the same time easier. The equipment owner is dissatisfied with leak rates of ■■regulated substances and their high costs, and therefore wants to avoid releases of large amounts of ODS. The equipment owner has environmental policies and ■■wants to make a long-term plan to move out of ODS. Multinational companies often have global policies to reduce their carbon footprint, and improving their RAC systems can have a significant positive impact. The equipment owner wants to avoid the risk of a work ■■standstill due to future shortage of ODSs when they have an urgent servicing need. The equipment owner is pushed by authorities and/or ■■regulations to phase out all ODSs. The age of the equipment, the time perspective and financial situation of the system owner will result in anything from low cost “fix it cheap” solution to the replacement of the whole system to obtain a high energy efficiency.It is always important to evaluate the suitability of the existing plant before a retrofit is made. The age and status of the system are key factors in the decision-making process. For the first project, a carefully followed procedure might take some extra time but it will quickly pay off, since a failure to do the proper “homework” tends to result in an increased failure rate. If the documentation of performance and operation is not done prior to retrofit, there is no possibility to build experience for the future. If a failure or problem occurs it is often impossible to know afterwards if the cause of the failure was due to the change of refrigerant, the servicing methods used or if the problem existed before the refrigerant change started, in which case the system would have failed anyway. The contractor, refrigerant or method used can then be incorrectly blamed even if the reason was that, for example, the compressor was in poor shape. The following steps should be considered before undertaking any retrofit (adapted to the size, status and cost of equipment): 1.6 Retrofit procedures and transported around the system. This can result in compressor failures or poor functioning of expansion and solenoid valves. The use of filters in the suction line, and replacement of both the filters and the filter driers, are often recommended. If retrofits are done with flushing (as described in the following sections) the risk from old contaminants decreases. It would be an advantage to avoid oil totally, and there are a few types of oil-free systems on the market. These designs have been used in large centrifugal compressors that operate without oil (except for small amounts in shaft seals that can enter into the system in small quantities). Lately a new type of smaller (a few hundred kW cooling capacity) oil-free semi hermetic centrifugal compressors with magnetic bearings has been introduced in the RAC market. P. 1.11 For old plants in poor condition and/or with high leakage rates, retrofits might not be a justified option even if the cost is limited. Often the better energy efficiency of a new system can quickly compensate for the additional capital investment.