Increasing the energy efficiency of air conditionig and refrigeration systems

22.09.2007.

Measures for increasing energy efficiency are also becoming more and more important in air-conditioning and refrigeration applications. Against the backdrop of global climate change, one should not neglect the potential for reducing CO₂ emissions which can be achieved through optimized air-conditioning and refrigeration technology. Today in the USA, some 14% of the total electrical energy is used to air-condition buildings (source: Annual Energy Outlook 2007 Report).In fully air-conditioned buildings, the operating and maintenance costs exceed the construction costs after only several years nowadays. Air-conditioning systems consume a lot of energy to generate low temperatures. As a rule, they are powered by electricity, which means that high conversion losses occur when the electrical energy is generated from fossil fuels.

The new A/F Armaflex: even more energy efficient

There are various measures and concepts for lowering the energy consumption of refrigeration and air-conditioning systems. Optimal insulation has an important role to play in the general concept for operating refrigeration equipment as energy efficiently as possible and reducing energy losses. It ensures that the required operating temperature is maintained for as long as possible, thus reducing the need for the refrigeration machine to start up in order to lower it. Whilst today low-temperature insulation mainly serves to prevent condensation, in future avoiding energy losses from installations will become a primary objective.

In this context, the development of the new improved AF/Armaflex is a groundbreaking innovation. With its improved technical properties of l0°C ≤ 0.033 W/(m·K) and µ ≥ 10,000, the new AF/Armaflex is up to 10% more energy efficient than traditional elastomeric products. Armacell ensures that these exceptional technical values are maintained through continuous internal and external monitoring. The energy loss from installations which are insulated with the new AF/Armaflex may rise slightly in the course of the service life, but after 10 years it is still lower than the initial energy loss (‘dry’ initial value) when an insulation material with a higher thermal conductivity and lower µ-value is used. So the improvement in the µ- and -values has considerable impacts on the long-term behaviour of the insulation system.

Armacell study on the potential for saving energy through optimized pipe insulation

To identify the energy-saving potential which can be achieved by insulating the chilled-water lines of air-conditioning systems, Armacell has undertaken its own study. A typical application was taken as the starting point for the investigation: a supermarket with a floor space of 9,000 m² and a cooling requirement of 70 W/m² is cooled by a 505 kW air-conditioning system with a nominal supply temperature of +6°C. The total length of the chilled-water pipes, which have various diameters, is 608 m. At an ambient temperature of +26°C maximum and a relative humidity of ≤70 %, the insulation material AF/Armaflex AF-1 (7-10 mm) would normally be installed on the pipes to prevent the risk of condensation.

However, contrary to common belief, the insulation thickness needed for condensation control is not the optimal solution as far as energy savings are concerned.

Saving potential through higher level of insulation over a period of 15 years
Electrical energy (kWh) 153.432
Financial savings (Euro) 23.219,87
CO₂ reductions (kg) 104.794

Additional savings can be achieved with a greater insulation thickness, as the graph on page 1 shows. In the given conditions, AF/Armaflex insulation AF-4 (20.0-23.5 mm) is the optimum. The slightly higher investment costs have paid off after only 5 years. Assuming an annual rise in energy prices of 5%, € 23,200 can be saved over a service life of 15 years. Translated into CO₂ emissions, this represents a reduction of around 105 tonnes, which is roughly equivalent to the CO₂ emission of an average single-family house over a period of 10 years.

The energy consumption of refrigeration and air-conditioning systems is enormous. Yet the operators are often not aware of this. Due to rising energy prices, the efficiency of the systems is becoming more and more important, because costs can be saved through energy-efficient systems. At the same time, they protect the environment. In the non-residential sector in particular, there is great potential for savings throughout the world. If this potential were realised, energy consumption could be reduced, the value of the property increased and a contribution to the security of supply and climate protection made.

Pogledajte kompletno Armacell istraživanjeenergyefficencycoldsystemsen2007.pdf

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