Increasing the energy efficiency of air-conditioning and refrigeration systems
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.
Reduce energy losses with Class O Armaflex
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.
A low-temperature insulation system protects equipment against condensation. In addition, 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.
As the moisture content of the material increases, the thermal conductivity rises, the insulation effect deteriorates and higher energy losses occur as a result. Insulation materials for refrigeration systems should therefore be closed-cell and have a high resistance to water vapour transmission (µ) and a low thermal conductivity (). In the case of Class O Armaflex, the resistance to water vapour transmission is built up steadily - cell by cell - throughout the whole material thickness. The cell walls are ‘sealed’ during the production process, allowing a very high resistance to water vapour transmission to be achieved. Armacell has been able to constantly improve the technical properties of Class O Armaflex and today guarantees a resistance to water vapour transmission of µ 7,000 and 0°C ≤ 0.034 W/(m·K). The product is subject to continuous internal and external monitoring. This means that Armacell can guarantee the excellent technical values reliably and for the long term. Model tests carried out internally and externally have shown that even after it has been installed for as long as 20 years Class O Armaflex still has the values guaranteed at the time of manufacture.
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 Class O Armaflex 9mm 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 a higher level of insulation over a period of 15 years
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Class O Armaflex 19mm |
| Electrical energy (kWh) |
153 432 |
| Financial savings (Euro) |
23 219,87 |
| CO 2 reductions (kg) |
104 794 |
Additional savings can be achieved with a greater insulation thickness, as the first graph shows. In the given conditions, Class O Armaflex insulation 19mm 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.
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