Household and laboratory appliances (refrigerators and freezers, tumble dryers)

This section is primarily concerned with small refrigerators and freezers of the kind found in millions of households. It also describes refrigerator and freezer units developed specifically for laboratories, since the refrigerant situation here is different from that of household appliances. It does not consider other laboratory applications which also contain (fluorinated) refrigerants. In addition to refrigerators and freezers there is also another common appliance which contains refrigerant: the tumble dryer with integrated heat pump. These appliances are also described briefly.

Today refrigerators and freezers are found in almost every household in Germany, and also in many offices and other areas. Manufacturers around the world produce more than 100 million appliances a year, and the number of existing appliances is put at 1,500 to 1,800 million [UNEP 2009]. The appliances available on the market vary in size and equipment. As a rule the insulating material used is polyurethane (PUR), and refrigeration is by means of hermetic, permanently enclosed systems (compressor systems).

Also on the market, in addition to the appliances used largely in households, are refrigerators and freezers developed specifically for laboratories. These have to comply with special requirements compared with household appliances. Examples include exact temperature control, rapid cooling to target temperature, explosion protection etc.

Heat-pump tumble dryers have only been on the European market for a few years. Their market share is growing steadily, and the figure for Germany in 2008 was just under 6%

[EEDAL 2009]. Compared with conventional tumble dryers, the capital cost of appliances with integrated heat pumps is higher, but they offer energy-saving potential of up to 50%, so the total cost of heat-pump tumble dryers over their entire life cycle is lower [EEDAL 2009a].

The refrigerant in heat-pump tumble dryers, mostly 407C, but also 134a, HFC-410A and HFC-152a, is contained in a hermetically sealed system. Refrigerant charges range from 300 g to 600 g.

Until the early 1990s, CFC-12 was used as a refrigerant in household and laboratory appliances working on the compression principle, and CFC-11 was used as a blowing agent for the manufacture of thermal insulation materials. For a short time manufacturers used HCFC-141b as a blowing agent instead of CFC-11 because of its lower ODP. Since the ban on CFCs, they have used HFCs and halogen-free refrigerants and blowing agents.

Approximately 63% of all household refrigerators and freezers produced worldwide still use HFC-134a, while about 1-2% use HFC-152a and HCFC-22. However, experts estimate that by 2020 some 75% of household appliances will be using hydrocarbons as refrigerant. Every household appliance contains between 50 g and 250 g of refrigerant [UNEP 2009]. Like CFCs, HFC-134a is not combustible. There is therefore no need for explosion-proofing measures during production or in the product. Laboratory appliances usually contain HFC-134a and HFC-404A.

In Germany, household refrigerators and freezers are not important as a source of HFC emissions. Only very few appliances using HFCs are on the market (see further below). They are nevertheless included in this report because of their fundamental importance and because of the use of HFC in other countries. Although existing laboratory appliances mostly contain HFC as refrigerant, their significance as a source of HFC emissions is fairly low because of their relatively small numbers, small refrigerant charges and good disposal facilities.

Reduction options

In Germany, the complete changeover of conventional compressor systems in the household appliances sector to CFC-free refrigerants took place in 1993/94. After using the refrigerant HFC-134a for a short period, all German manufacturers went over to using the hydrocarbon R 600a (iso-butane). Since the mid 1990s (1993/1994), pentane or cyclopentane (c-pentane) have been used as a blowing agent for insulation materials. No appliances containing HFCs are produced in Germany [BSH 2003].

The technical design of the appliances underwent changes, at least in detail, with the introduction of hydrocarbons as the new refrigerant. For example, it was necessary to cater for the flammability of hydrocarbons. Moreover, the stricter requirements for the energy efficiency of refrigeration systems also resulted in product modifications (improved compressors, reduced heat transfer losses, better insulation etc.) [UNEP 2003]. Modern appliances with hydrocarbons as refrigerant and blowing agent satisfy the requirements of energy efficiency classes A+ and A++.

Over a period of more than 15 years, appliances with hydrocarbon refrigerants have demonstrated their safety and their economic and environmental viability. No system-related technical problems are known [UNEP 2006]. Safety concerns nevertheless continue to be discussed from time to time in other European countries; in some countries outside Europe, the use of combustible refrigerants is a problem because of existing national regulations. This also applies to quantities of less than 150 g hydrocarbon per appliance [BSH 2003]. This situation could change, at least in the USA, because in May 2010 the Environmental Protection Agency (US-EPA) proposed under the U.S. Significant New Alternatives Policy (SNAP) that isobutane and propane be listed as acceptable alternatives to CFCs in household and commercial refrigeration appliances (up to 150 g). The hydrocarbon technology was successfully introduced some years ago in other countries, especially China and India.

No publications exist on the costs arising in practice from the changeover to hydrocarbons.

Basically, additional costs arise from safety precautions needed for the transport and storage

capital cost), and necessary modifications to the product design (development work) and the components used. Other significant cost aspects are disposal, energy consumption and the refrigerant. With regard to disposal and refrigerant costs, the use of hydrocarbons results in a reduction; there is no significant change with regard to energy consumption.

Apart from appliances with compressor systems, there are isolated appliances on the market with other technologies, so-called “not-in-kind technologies”. According to UNEP [UNEP 2006], these include absorption systems mostly using ammonia/water (see Chapter 3.1.2), appliances using the Stirling process, thermoacoustic and thermomagnetic appliances, and appliances using the transcritical CO₂ process. Some of these technologies have also become state of the art. In terms of costs and specific energy consumption, however, these “not-in-kind technologies” are still not competitive for mass production by comparison with compressor systems [UNEP 2006]. Nevertheless, absorption appliances in particular are used primarily in the hotel and camping sectors because of their quiet operation. But their numbers are very small compared with appliances using compressor systems [UNEP 2003].

Some appliances, especially those produced in former East Germany, were insulated with expanded polystyrene instead of PUR insulating material. No halogenated substances are used in the production of expanded polystyrene. These appliances are an exception, however. In view of the poorer energy efficiency of the appliances with expanded polystyrene, the manufacturers did not pursue this technology any further.

Until 2008, laboratory appliances were only available with HFC. Since then, various European manufacturers have put appliances with halogen-free hydrocarbons on the market, which means that – according to information from the suppliers – the entire product range is now available with these refrigerants. These appliances are notable for their high energy efficiency and hence lower operating costs, and do not cost any more to buy [Gram 2010;

MSL 2010].

To date, no heat-pump tumble dryers with natural refrigerants are available on the market, but tests have been performed with hydrocarbons, CO₂ and water. The use of hydrocarbons, e.g.

propane, looks very promising because it permits further energy savings compared with present-day dryers using HFC. One objective of the development work with hydrocarbons is to reduce the refrigerant charge below 150 g [EuP Lot 16; Siemens 2009].

Conclusions

Even before 1993/94, German manufacturers put CFC-free and HFC-free refrigerators and freezers on the market. Today such appliances are manufactured in various European countries, and also worldwide. They have demonstrated their economic and environmental viability. Other European and non-European manufacturers (e.g.

manufacturers in the USA) continue to use HFC-134a as refrigerant and in the insulating material. Some of these appliances are also available in Germany.

For a few years now, HFC-free refrigerators and freezers complying with the special requirements for laboratory use have been available on the market. Their energy

In the case of tumble dryers with integrated heat pumps, the use of natural refrigerants, especially hydrocarbons, would seem to be possible and to make sense from an economic and environmental point of view. Further research is necessary to develop such appliances.

There is no need to use HFCs either as a refrigerant or as a blowing agent. When buying an appliance, therefore, the choice can and should go in favour of HFC-free products with high energy efficiency.

A large proportion of end-of-life appliances still contain CFCs, and in some cases HFCs.

In the course of disposal, these substances must be recovered and destroyed with a minimum of emissions.