It is common knowledge that considerable energy savings can be
achieved through the optimal insulation of buildings. However the
energy saving benefits of insulating air conditioning and
refrigeration systems are sometimes overlooked, with structural
insulation requirements more readily considered. Yet it is
investments in the insulation of HVACR service equipment that are
recovered much faster. This is equally true for refrigeration and
air-conditioning as it is for heating systems.
Buildings account for almost half of energy consumption and carbon emissions in the UK and air conditioning and refrigeration in buildings account for up to a third of annual electricity costs (Department for Communities and Local Government, Guide to Reducing Energy Emissions in Businesses). Any measures to increase energy efficiency in this area therefore have great environmental and cost saving potential.
The insulation of cold pipes is usually aimed at preventing condensation, with insulation thicknesses of 6 to 13mm being common practice to control condensation. However as the results of a recent study carried out by Armacell show such thicknesses are not optimally designed to reduce associated energy losses, with substantial energy and CO2 savings possible when thicker insulation materials are used.
The objective of the study was to find an optimal, cost-effective insulation thickness for various types of plant. For this purpose, Armacell determined the savings which are achieved through the use of thicker levels of insulation. These savings were then compared with the cost of investment. A wide range of applications were tested, incorporating building air-conditioning systems with different cooling demands, together with typical refrigeration systems used in supermarkets for food and drink storage.
THE RECOVERABLE COSTS OF OPTIMAL INSULATION THICKNESSES
Irrespective of the complexity of the system and the cooling demand, an optimal insulation thickness of 15.5 to 25.0 mm Armaflex insulation was determined for chilled-water pipes. The higher investment for this thicker insulation pays for itself in the course of the service life, accruing considerable financial savings after only a few years. For refrigeration system pipework an even thicker level of insulation pays off and for these applications Armacell recommends 32 to 50mm as the optimal insulation thickness. Even at this level of thickness costs are recoverable after just 7 to 9 months of normal plant operation.
CONSIDERABLE POTENTIAL FOR CO2 SAVINGS
Unsurprisingly the results are also extremely favourable from an environmental point of view. CO2 emissions from the systems investigated were reduced by several tonnes annually, just by insulating the pipes to the optimal thickness. These findings allow the following generalisations about the environmental performance of the insulation material.
Per installed cubic metre of Armaflex, the use of optimal insulation thicknesses allows annual CO2 savings of:
• approx. 1,150 kg in the operation of air-conditioning systems,
• approx. 1,900 kg in the operation of refrigeration systems with a line temperature of -5 °C and
• approx. 2,550 kg in the operation of refrigeration systems with a line temperature of -36 °C.
The study clearly shows that considerable potential for savings exist through the use of optimal insulation levels in refrigeration and air-conditioning applications. Moreover, the investigation findings were not achieved on specialised equipment, but with standard commercial systems. In future, the objective when insulating pipes in cold applications should therefore not only be condensation control, but also energy saving for sound economic and ecological reasons.
Armacell is a manufacturer of engineered foams and the world market leader in the field for flexible technical insulation materials. Headquartered in Münster, Germany, Armacell has a gross annual turnover of around €399 million, employing 2,300 people worldwide, with 18 factories in 12 countries. Apart from ARMAFLEX, the leading brand in the field of flexible technical insulation, the company also produces thermoplastic insulation materials, covering systems, fire protection and noise control products and special foams for a multitude of industrial applications.
Further information or a copy of Armacell report ‘Considerable Energy Savings through Optimal Insulation of Air-Conditioning and Refrigeration Systems’ is available by email.