Usually the facility management contract talks about how to manage the systems and equipment in the facility and how to keep them running smoothly. However, in many cases it overlooks the energy management and energy efficiency best practices. The facility owner for their benefit and for the environment benefit should include clauses in the contract talking about the required services from the facility management company for energy management and energy efficiency.

The facility management company should have knowledge and experience in energy management so they can save their clients money from the running cost of the systems and equipment in the facility and also they should be committed to preserve the environment for the coming generation. The climate change is real and energy efficiency/sustainability became essential for most of the facility owners and who denies that will be left behind.

So, what we need to include in the facility management contract for energy efficiency? We have summarized below main points that need to be included and the facility owner can modify/add to this list based on the type of the facility and its systems and equipment:

• Energy Audits: The contract shall have clause taking about periodic energy audits to the facility. Energy audit analyses the facility energy consumption and identify any anomalies or any energy saving opportunities. It also inspects the systems and evaluates their efficiencies and determines when an equipment needs to be replaced with higher efficiency type if that has a good return on investment. These energy audits can be conducted by the facility management company staff if they are qualified to do so or they can hire an energy consultant to do it for them. Click here for more details about the energy audit.
• NABERS Energy & Water Rating: NABERS rates the building in a scale from one to six stars based on its energy consumption and compared to other similar buildings. NABERS rating tells the facility owner as well as the facility management company how far is the building from the best performing buildings and whether there are opportunities to save energy and improve the building efficiency. The rating can be done by accredited assessors from the facility management company or they can hire NABERS accredited assessor to do it for them. Click here for more details about NABERS Rating.
• Schedules for Recommissioning and Maintenance: The contract should talk about scheduling recommissioning and maintenance to the facility systems and equipment to make sure they are tuned for the best efficiency.
• Energy Efficiency Action Plan: The contract should talk about preparing energy efficiency action plan to set realistic targets to implement energy conservation measures in accordance with the budget available from the facility owner.

Off course the above additional services will increase the facility management contract value but it will save the facility owner a lot of money in the running cost and in the same time, preserve the environment for the coming generations. Further, implementing energy conservation measures in the facility and NABERS energy rating for the facility increases the asset value and attracts more tenants to the facility so, it is an investment and not a waste of money.

One of the control strategies for the HVAC system that should save energy is the supply air temperature reset. By this strategy and during the cooling mode for example, the controller increases the supply air temperature in the AHU when the cooling load in the building decreases. By this way, we decrease the load on the chiller, which leads to reduction in its energy consumption. This strategy work very well and for sure saves energy in the constant air volume systems but what about the variable air volume (VAV) systems?

In the VAV system, the AHU fan speed decreases when the load decreases in the building to save energy and it is controlled by a pressure sensor in the supply duct. When the VAV boxes start closing due to the low load in the building, the pressure increases in the supply duct and the pressure sensor send a signal to the controller to decrease the fan speed.

From the above we can see that resetting the supply air temperature is fighting the fan speed reduction strategy when the load in the building starts decreasing. So, does the supply air temperature reset strategy really reduces energy consumption? Is the saving in the chiller energy more than the fan energy increase? If we keep the supply air temperature constant without a reset, does the fan energy saving exceeds the energy required for the reheat coils? It is hard to tell unless we measure the actual energy consumption of the system before and after we implement this strategy or we might use energy simulation software to predict the energy consumptions with and without this strategy.

Some BMS (Building Management System) experts say that by implementing supply duct pressure reset strategy and with a good fine tuning to the control system, the supply air temperature reset can work properly and decrease energy consumption.

This can also apply to the supply chilled water temperature reset in variable water flow systems because it has the same concept as the supply air temperature reset. Actually, they are connected together. When we reset the supply air temperature in the AHU because of the low load in the building, the chilled water two-way valve of the AHU start closing. This will send a signal to the controller to reset the supply chilled water temperature, which will fight the strategy of reducing the chilled water pump speed.

If you have anything to add for this blog, please feel free to leave your comment below:

Most of the light commercial buildings have packaged air conditioning units or ducted split air conditioning units. These units mostly fall in the capacity range of 15 kW to 90 kW and usually they are reverse cycle heat pumps to provide cooling in summer and heating in winter. When I drive around the suburb I live in Melbourne, I find numerous light commercial buildings that have either packaged or ducted split air conditioning units and most probably these units are as old as the buildings themselves and never been inspected for energy efficiency. This is in one suburb only so imagine how many light commercial buildings we have in Melbourne metropolitan or even in all Victoria. If you do the math you will find that we can save substantial energy by replacing the old inefficient air conditioning units in these small buildings with new high efficiency type.

These light commercial buildings are usually rented and the tenants don’t have the authority to approve the replacement of these units and also they don’t want to pay for the cost of the replacement. Likewise, the landlord is not welling to replace these units because they don’t pay the energy bills and the tenant pays for that. Therefore, it is lost between the landlord and the tenants and they keep run these units even if it is not efficient and waste a lot of energy.

I see some companies of LED lights and solar PV systems approach these buildings for replacing their old lights or install a solar PV system for them but I have never seen a company approach these buildings to inspect the air conditioning units and offer replacing them with higher efficiency units even though there is a government rebate scheme for such replacement in some states such as Victorian Energy Upgrade Project in Victoria.

I don’t know who to blame here? Is it the air conditioning contractors and maintenance companies, the energy consultants like us or the government for not advertising for their rebate schemes for the air conditioning units replacement?

The new high efficiency air conditioning units for these light commercial buildings come with variable speed compressors and also with variable speed supply fans, which make it very efficient. The manufacturers claim that these high efficiency units can save up to 37% in energy consumption compared with the old inefficient units. For example for a unit of 35 kW cooling/heating capacity, this equals to around 5,000 kWh energy saving and around $1,000 cost savings per year per unit. This also will result of 5.4 Tonnes CO2 avoidance of greenhouse gases emissions per year. These savings only from one unit but imagine how many units each building have and how many small buildings we have then this let us think about it seriously and how to get these old air conditioning units replaced.

In our opinion, the government has the main role to make this happens by increasing the rebates and incentives for the replacement of the old air conditioning units to encourage the landlord/tenant to replace these old units and also they should advertise about these rebates to make the landlord/tenants and the air conditioning maintenance companies aware of these rebates. The air conditioning maintenance companies have also an important role in convincing the landlord/tenant to replace the old units with new high efficiency units. Finally, the energy consultants like us should also reach out to the building owners to inform them about these rebate schemes and how replacing the old unit with new high efficiency unit will save them money and in the same time help protecting the environment for the coming generations.

For a comprehensive inspection and review of your air conditioning system, don’t hesitate to contact us.

I was reading the other day an article in AIRAH Ecolibrium Magazine (December Issue) about building a district cooling plant for the University of Queensland Gatton and it was great system that provides chilled water to the university campus in efficient way. This article let me wonder whether we can apply the district cooling and heating concept (i.e. District Energy) in a large scale here in Australia and provide chilled and hot water as a service. This let me to think more and I came to the following discussion points:

• The district cooling plant usually uses water cooled chillers, which are more efficient than the air cooled chillers. However, most of the high rise buildings in the Australian capital cities uses also water cooled chillers and not air cooled chillers due to the high cooling capacity required. Have a look for example, on the Melbourne CBD buildings in Google Earth and you can see that most of the buildings have cooling towers on the roof. Further, the district cooling plant requires a fair area of land to be constructed on specially if it has thermal storage tanks, which is hardly available in the CBD of the major cities and if it is available, it would be more feasible to build a tower than a district energy plant. This let me think that district energy plant is not suitable for the cities CBD unless you are building a number of buildings next to each other in one time, then you can build an energy plant to provide chilled and hot water to these buildings.

• This let me think about what if we implement district cooling and heating to the suburbs of the major cities. It is easier to find a land in the suburbs to build the district energy plant but not all the people in the suburbs will buy chilled water and hot water. The weather in Australia is not that extreme and many people use for example, ceiling or pedestal fans in summer instead of air conditioning. This led me to think that this concept will not be financially viable in the suburbs. I had previous experience working in district cooling field in the Gulf Countries (in the Middle East) and the weather in these countries is very extreme where the people can’t live without air conditioning and need cooling day and night and that is why the district cooling concept is financially viable in such countries.

• Laydown the chilled and hot water piping network under the ground to connect it to the existing buildings and houses will not be an easy task. It requires high level of coordination with the other existing services such as sewage, natural gas, water supply, communications…etc, which make it very expensive and time consuming.

• The district cooling plant consumes a large amount of water because it loses water through evaporation in the cooling towers, which imposes stress on our water resources unless we use treated sewage effluent water.

Based on the above discussion, we conclude in our opinion that district energy is suitable for the following building types in Australia:

• University Campuses in which multiple buildings require cooling and heating most of the time of the year.
• Hospital Campuses similar to the university campuses above.
• New large developments located in extreme weather such as Queensland and Northern Territory and have the underground networks for the chilled and hot water included in the design stage.