The Need For and Sources of HVACR Energy Efficiency

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Tuesday, January 27th, 2015
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In the Australian Refrigeration Association’s October newsletter, we described the opportunity for Australia to reduce the cost of HVACR energy use by $10 billion per annum.

Most importantly, we noted the fact that the industry is transitioning to low emissions technology because doing so will reduces HVACR energy consumption and GHG emissions. They are two sides to the same coin. Low emissions HVACR technology is energy efficient technology.

Since that newsletter came out, there has been considerable evidence of and impetus to change driven by international agreements. China and the US have agreed a broad agenda of emissions reduction including the commitment to phase down the use of HFC refrigerants. This agreement is similar to the initiative by the European Union to phase down HFC use by 79 per cent by 2030.

The Climate and Clean Air Coalition, comprised of 40 countries in association with UNEP, including Australia, has endorsed this policy and established an international working group specifically for the purpose. As a result, original equipment manufacturers worldwide are embracing the need to deliver refrigeration and air conditioning systems that are based on low-GWP refrigerants.

The Montreal Protocol is considered the most likely vehicle for delivering the transition to low-GWP refrigerants. A recent meeting of the parties to the Montreal Protocol saw movement in this direction to the extent that most commentators consider this development to be inevitable. It makes a great deal of sense because the Montreal Protocol is considered to have caused greater GHG emissions reduction than all other climate change policies combined.

Because the parties to the Montreal Protocol include 197 countries in both the developed and developing world, it provides an excellent framework for the global phase down of HFC refrigerants. Central to this is the opportunity for developing countries to leapfrog HFC refrigerants and transition directly from ozone depleting refrigerants like R22 to low-GWP refrigerants. Australia can play a leading role by demonstrating and in fact supplying low-GWP refrigerant based technology throughout the Asia Pacific region.

The transition to low-GWP refrigerant-based technology seems inevitable. It is broadly supported by the HVACR industry not least because it will deliver energy efficiency. The low-GWP refrigerants, HFO synthetic refrigerants and the natural refrigerants, ammonia, carbon dioxide and hydrocarbons are themselves far more energy efficient than high-GWP HFC refrigerants.

It is also important to keep in mind the wide range of technologies that deliver HVACR energy efficiency. The ARA has completed a series of seminars focussed on this strategy wherein we recommended the adoption of integrated energy efficiency engineering based on life cycle costing and life cycle management of all of the technologies that contribute to HVACR energy efficiency. It is our view that building managers from property developers to building designers, facilities managers and energy services consultants need to embrace this strategy for increasing HVACR energy efficiency.

We proposed three categories of consideration:

  1. Energy efficient vapour compressions systems
  2. Integrated with better energy measurement and management
  3. Better heat load management technologies. Integrated energy efficiency engineering calls on building designers and retrofit investments to recognise that all three categories need to be considered and integrated in order to optimise the energy efficiency of a given facility.

There are important technology developments in all three categories.

HVACR Energy Efficiency Solutions

The degree of energy savings available is of course unique to each building. However, we can identify generic solutions and provide indicative energy savings.

Better Energy Measurement and Management

The starting point is better energy measurement and management. It is obvious that building managers need to measure energy consumption and the specific sources of energy consumption in order to better prioritise energy savings opportunities. New energy measurement technology is now available that enables continuous and remote monitoring and control of energy consumption.

This development has the potential to dramatically change the structure of the HVACR industry because it enables the building manager, or his energy services consultant or his HVACR contractor to know and control HVACR operations. The sources of wasted heating, cooling and refrigeration can be identified and avoided. The degree of savings available has been to shown to be in the order of 20 per cent in a wide range of facilities.

There are many suppliers of better energy measurement and management systems. The field is bound to be dynamic for the foreseeable future and fundamental to energy efficiency initiatives.

Energy Efficient Vapour Compression

A very large proportion of the built environment HVAC requirement involves split system air conditioning. There are about 12,000,000 split systems installed in Australia spanning a considerable range of age and engineering sophistication, but the vast majority are fixed speed systems using HFC refrigerants. These can be replaced by hydrocarbon based split systems that are as much as 40 per cent more energy efficient. In fact, a large proportion can be retrofitted so as to incorporate hydrocarbon refrigerants and variable speed drives. The combination can be as much as 70 per cent more energy efficient that the existing systems and the capital cost of a retrofit is about 30 per cent lower than a complete replacement.

The same principle applies in high-rise facilities that use chillers based on synthetic refrigerants. These can be replaced or retrofitted to employ natural refrigerant based systems that are up to 40 per cent more energy efficient. Ammonia systems have been shown to be both highly efficient and have very high capacity. Similarly, hydrocarbon retrofits have been shown to deliver similar energy efficiency. As a result, it is no longer necessary to use HFC-based chillers that are less energy efficient.

District energy solutions offer substantial opportunities to combine the heating and cooling facilities of centralised plants that generate energy or use waste heat as a source of energy efficiency. Australia has been slow to embrace the opportunity of district energy but there are clear examples of success in Australia and substantial proof available in Europe. The cost savings can be up to 50 per cent, serving a number of large buildings with a centralised plant; itself a contribution to cost effectiveness.

Cool Rooms and Cold Stores

There are about 100,000 cool rooms and cold stores in Australia. The vast majority use energy inefficient HFC refrigerants. By converting large cold stores to ammonia refrigeration or smaller cool rooms to hydrocarbon refrigeration the energy savings can be in the range of 30 to 40 per cent.

These solutions have been demonstrated broadly in Australia and are now considered proven technology.

Commercial and Industrial Refrigeration

Commercial refrigeration spans a considerable range in capacity but there are energy efficient solutions available across the entire range from stand alone equipment to large commercial and industrial refrigeration. Perhaps the best example of this trend is the commitment of the Consumer Goods Forum to the use of natural refrigerants. This organisation enables over 400 of the world’s largest food retailers and food suppliers to collaborate to identify ways to reduce energy use and emissions. The CGF has committed to transition to natural refrigerants in all of its HVACR applications because they want to energy savings and are committed to emissions reduction.

Heat Load Management

A major opportunity in HVACR energy efficiency is to reduce the heat load in the building where heating and cooling is required. There are many important solutions for this purpose and the technology available is changing rapidly in response to the demand for energy savings.

The concept of heat load management in Australia is largely about reducing the heat load in a building by better managing the ingress of high ambient temperatures. The solutions include better roof heat management, double-glazed windows or windows that employ reflective surfaces, reflective paint on roofs and walls that have high solar exposure and low heat lighting. Each of these solutions can reduce the cost of air conditioning and refrigeration quite significantly, in the order of 10 to 20 per cent.

Together, and in association with more energy efficient energy management and more energy efficient vapour compression systems, the HVACR energy savings can be as much as 70 per cent.

The Challenge

There are many challenges to achieve this degree of improvement but the most important is for building owners and operators and their energy services suppliers to recognise and embrace the opportunity of integrated energy efficiency engineering. At the same time, government has a major role to facilitate the transition to energy efficient HVACR through regulations and subsidies that serve to demonstrate the value throughout government agencies and industry, residential suppliers of HVACR services. There is an enormous training and education task to reach this highly decentralised and economically important function.

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