Consulting since 1992
Integrated Energy Systems
SmartConsult has worked closely with Scantec Refrigeration to develop an Integrated Energy System to increase the efficiency of energy usage in Aquatic Centres. In the past plant in these centres worked independently of other plant resulting in overlap and wastage of thermal energy that had been paid for. These systems had been acceptable whilst gas prices were low, however a sharp rise in gas prices in July 2018 forced some venue operators to review their energy usage and start to look more closely at alternatives.
The system is capable of reducing energy usage in centres by more than 50%. The combination of plant efficiencies and the recycling of energy in the building allows centres to move their budgets back towards the black. A situation that has been out of reach for centres until now.
What is a COP?
You will have seen the energy rating stars on household appliances. These are rating the appliance with regard to how many times greater than 1 that appliance is for energy consumption. The more stars it has, the more efficient the appliance is. We use a more specific measure for energy efficiency with thermal systems and it is called the Coefficient of Performance: the COP.
This is a measure of how much useful thermal work is done by a machine for a unit of electrical energy 1kW of power. An electric water heater that you see in most houses has a COP of 1. A gas water heater will have a COP of about 0.85. But an integrated heat pump for heating water can have a COP of more than 11, as you add the energy from the hot and cold that is produced. This means that for every 1kW of electricity that you use, the system will produce a combined 11kW of heating and cooling. The compressor is not ‘making’ the energy: it is transferring the energy from the air surrounding the building to be used somewhere else, such as the pool or a weights room.
It’s all about balance in the system
A water to water heat pump produces hot water and cold water. The hot water can be used in the pool and also for heating air in the centre. There is an additional supply of hot water available at 80 deg C that is produced as a byproduct. This water is a smaller supply and is ideally suited to hot water systems, as this water must be heated to 60 deg C for health reasons. At some times of the year, such as in winter, the full ‘cold’ load is not required. So this cold needs to be dumped from the system. At the peak of summer, the system may need to dump heat as all of the heat is not required. When this dumping occurs, the system is not as efficient as this dumping of energy is a ‘loss’. But overall, the system is balanced most of the time and is working near optimal efficiency. And at peak efficiency the system is 11 times more efficient than a gas hot water system coupled with the additional cost of airconditioning.
How an integrated system handles energy
This diagram shows the change in energy usage when a water heating system (gas) and an air conditioning system are integrated. The gas is fully removed and integrated system has a lower electrical input. These are round figures and do not take into account the inefficiencies such as discarding waste cold during winter. But overall, this is how the system handles the energy over a full year.