Air Conditioning Inspections to Improve the Energy Efficiency of our Buildings
Are Air conditioning assessments beneficial?
Air conditioning inspection requirements, why are air conditioning inspections required?
Having an air conditioning system inspected by an accredited air conditioning energy assessor is designed to improve efficiency, reduce energy consumption, operating costs and the carbon emissions of the system. The energy assessor will highlight improvements to the operation of existing systems or opportunities to replace older, less energy efficient systems or oversized systems with new energy efficient systems.
As the replacement of refrigerant is restricted in older systems (as established in other legislation), there is an additional incentive to improve or replace older systems with more modern energy efficient units. The person who controls the operation of the system, such as the building owner or manager, has statutory obligations and duties of care in the operation and maintenance of air conditioning systems. The inspections referred to in this guide are in addition to the normal activities associated with the ownership and operation of air conditioning systems. Regular maintenance and cleaning helps maintain the ability of the system to provide healthy and comfortable environments for building occupants, limiting the escape of refrigerant gases and ensuring the safety of equipment.
Assessing the energy performance of an air conditioning system. The inspection process. The air conditioning inspection process will examine the refrigeration equipment and air moving systems that are part of an air conditioning system, including their controls. Any documentation which helps to understand the system, or indicates the extent, to which the system has been maintained, will also be examined. The energy assessor is also required to estimate whether the system is suitably sized for the cooling loads in the treated spaces, and to provide advice on ways in which improvement might be made to the energy efficiency of the system.
The purpose of the inspection and resulting report are to ensure that the building owner or manager are provided with basic information that gives an indication of the likely efficiency of the air conditioning systems, together with some initial advice on how energy efficiency or effectiveness might be improved.
The report should be kept in a safe place and can be used to inform subsequent inspections. There is no statutory requirement to act on the recommendations in the air conditioning inspection report; however, the inspection and report will only benefit the building owner or manager if the findings are acted upon. The scope of an inspection on Air Conditioning plant and its associated heat exchange systems are checked briefly. The inspection looks primarily for indicators of damage or lack of maintenance that would significantly reduce their efficiency from their “as new” state and does not provide high level detail. Effective heat rejection is necessary to maintain the efficiency of the refrigeration system. If outdoor heat rejection equipment is damaged, or its access to adequate flow of air is otherwise reduced by blockage due to dirt or debris, its effectiveness in rejecting heat is reduced and its temperature will be unnecessarily high. This has the effect of reducing refrigeration efficiency, and reducing the cooling capacity of the system. It may cause an air conditioning system to turn off and on under the action of its own high temperature or pressure cut out, often without satisfying the building cooling load. Similarly, effective indoor heat exchange is necessary to maintain the efficiency of the air conditioning system. If this heat exchange equipment is damaged, or its access to adequate airflow is otherwise reduced, its effectiveness in transferring heat to the refrigeration cycle is reduced and its temperature will be unnecessarily low. This consequent reduced temperature at the indoor unit increases the temperature difference that the refrigeration cycle has to maintain, which has the effect of reducing the cooling capacity of the air conditioning system. It may cause the air conditioning plant to turn off and on under the action of its low temperature or pressure cut-out, often without satisfying the building cooling load. Air moving systems, where installed as part of the system to provide cooling, air moving systems is an important factor in the assessment. The contribution that fans make to the total annual energy consumption of the combined cooling system is likely to be higher than that of the refrigeration plant itself, and there may be a greater potential for improvement. The effectiveness of how air is delivered can play a part in determining the overall efficiency of the air conditioning system. Where delivery systems are ineffective, plant that is otherwise efficient, may operate for longer periods than necessary. However, the reverse may also be true, in that some delivery systems may interact unfavourably with occupants or control sensors, leading to reduced operation and consequent lack of adequate cooling. Improving some systems, even at good efficiency, could increase annual energy use.
Important factors to observe are the condition of, damage to, or blockage of filters and heat exchangers, and the fan type and method of control. Ventilation air delivery systems need free access to outdoor air.
Where grilles, screens or pre-filters are obscured by damage or debris, additional energy will be needed to overcome the extra resistance caused by the restriction to flow, or the system may under perform in other ways due to reduced air flow rates. Where systems provide cooled air, admitting air from locations where the local air temperature may be higher than ambient will add to the energy required to achieve cooling to the required temperature. Such locations might include positions near busy roads, in car parks, or where exhaust air from the building could be drawn into the air inlet.
Controls System controls are assessed in more detail. There could be considerable scope to identify inefficiency due to inappropriate control methods, incorrect control settings and poorly located sensors, and there could be much potential for improvement at low cost. Although discovered faults might be as simple as time switches or cooling or heating thermostats being incorrectly set, the energy assessor would not reset them but will report to the building owner or manager. An investigation of the realised effectiveness of system controls over any significant period of operation would be outside the scope of a simple inspection regime, but a series of physical observations of their layout and operation could give an indication of potential inefficiency, ineffectiveness or misuse. It might not be possible to investigate some aspects of the layout and operation of controls, particularly in more complex systems. However, sufficient of the following important issues should be accessible to a brief examination:
• the set temperatures to which the treated spaces are to be conditioned
• the time periods during which they are to be conditioned
• the appropriateness of the control zones, control sensors and their locations
• the potential for cooling to be operated at the same time as heating
• the method of refrigeration capacity control
• the method of air flow rate control
Where systems are controlled by a building management system, it may be necessary for the building manager to arrange for relevant aspects of this information to be extracted from the building management system prior to any inspection.
Documentation, the quality, extent and accessibility of relevant information provided before an air conditioning energy assessor visits an installation has important consequences for the effectiveness and may increase the cost of the inspection. Experience has shown this information is often missed and energy assessors have to spend time trying to locate relevant documentation. This is not effective use of the assessor’s time on site and without the information it is difficult to properly estimate the cost of an inspection. The air conditioning energy assessor will ask the building owner or manager to provide a list of relevant records, sight of the principle ones before visiting the site and for site records to be made readily available. Any available documentation for the air conditioning system must be provided prior to the inspection. This could include, for example, catalogue information and details provided during installation, commissioning and maintenance of the system. The quality and accessibility of relevant information provided before an inspection takes place may reduce the time taken to complete the inspection and may reduce the cost of an inspection.
Maintenance evidence of any existing planned maintenance schedule or of other recent maintenance activities will be sought. Where documentation clearly shows that equipment and systems are already the subject of regular good practice checking and maintenance procedures, a number of aspects of the energy inspection and provision of advice may be reduced in scale or omitted. Advice on improvement options.
Three levels of energy efficiency are likely to be found when systems are assessed:
• systems where efficiency is clearly impaired due to faults, neglect or misuse
• systems where efficiency is likely to be lower than current accepted minimum provisions due to aspects of design or use
• systems that are acceptably efficient
Correspondingly to these, there are three broad levels of advice that the building owner or manager may receive:
• advice on the rectification of faults in the system that are impairing its efficiency as designed
• improvement advice to bring existing systems broadly to a standard of ‘inherent’ efficiency consistent with the current minimum provisions of building regulations or standards
• best practice improvement advice to raise standards even where systems are fully compliant with the current minimum provisions of building regulations or standards.
A further category of advice which may also be given concerns some systems which may be older and operate with refrigerants which are being phased out, or having their use and supply restricted, under regulations relating to ozone depleting substances. In these cases the assessor may give advice on possible options for future system adaptation to use other refrigerants, or complete replacement. This advice will need to be supplemented by a more detailed assessment when modifications or replacement are to be undertaken.
Consumer protection and enforcement. Checking the authenticity of an air conditioning inspection report or an energy assessor. An air conditioning report must be produced by an accredited air conditioning energy assessor. The energy assessor must make a copy of the inspection report available to the client, or to the person who controls the operation of the system, as soon as practicable after the inspection date but only after the report has been lodged on the central register. The energy assessor may also make a copy of the report available to the accreditation scheme of which they are a member. All air conditioning energy assessors must be a member of an accreditation scheme. To check that an energy assessor is a member of an accreditation scheme a search facility is available on the central register website (www.ndepcregister.com). If a person does not have access to the internet they can ask the energy assessor for the name of the accreditation scheme of which they are a member and for their membership number. This information will enable the building owner or manager to confirm with the accreditation scheme that the energy assessor is accredited and fit and proper to practice as an energy assessor.
From 6th April 2012, it became a statutory requirement for the energy assessor to lodge all air conditioning inspection reports on the central non-domestic register. When the report is lodged it will be allocated a unique report reference number. Only air conditioning reports which were produced and lodged on the central register from this date are valid reports. Air conditioning inspection reports produced before 6th April 2012 may have been lodged on the central register on a voluntary basis. However, there is no statutory requirement for a valid air conditioning inspection report, which was produced before this date to be lodged on the central register. Statutory lodgement has been introduced to protect the consumer and to ensure that only accredited air conditioning assessors undertake inspections and prepare subsequent reports. Statutory lodgement will enable the building owner or manager to verify the identity of the air conditioning assessor and for accreditation schemes to monitor the standards of the reports which have been produced. Statutory lodgement will also enable lost and mislaid reports to be replaced easily at no additional cost to the building owner or manager. The building owner or manager will be able to check the validity of the report by accessing an on line copy of the inspection report and downloading a copy from the central register web site (www.ndepcregister.com) using the report reference number. A copy of the inspection report can also be downloaded from the central register using the building address from the register website, if the report reference number has been mislaid, unless the building owner has‘opted out’ of making the report available in this way.
Penalties for not having an air conditioning inspection report Local weights and measures authorities (usually through their trading standards officers) are responsible for enforcing the requirements relating to air conditioning inspection reports. Failure to commission, keep, or provide an air conditioning inspection report when required by the regulations means that a penalty charge notice may be issued to those in breach of the requirements. Trading standards officers may act on complaints or undertake investigations. They may request that a copy of the air conditioning inspection report is provided to them. If requested, the building owner or manager must provide this information within seven days of the request or be liable to a penalty charge notice for failing to do so. A copy of an air conditioning inspection report can be requested by an enforcement officer at any time up to six months after the last day for compliance with the obligation to make it available. The penalty for failing to having an air conditioning inspection report is fixed at £300.
Tenants of a building, where a central air conditioning system is under the control of the building owner or manager would not be liable for a penalty charge for any breach of the duties.
A further penalty can be issued for failure to provide a copy of the air conditioning inspection report when requested to an officer of an enforcement authority within seven days. This is fixed at £200. If a penalty charge notice is issued but that person believes it should not have been issued they can request a review. If that person is not satisfied with the outcome of the review they may appeal to the county court within 28 days after they are given notice confirming the penalty charge notice by the local weights and measures authority.
If the building owner or manager wants to sell or let a building with an air conditioning system, which should have been inspected, then it is very likely that the legal advisors to the prospective tenant or buyer will require sight of the report during the legal processes prior to exchange of contracts. Failure to have a report, where one is required, may have a negative impact on the transaction process.