Trigeneration (CCHP - Combined Cooling Heat and Power) is a technology for the combined generation of three types of energy simultaneously. In addition to thermal energy and electric energy (as in cogeneration), there is cooling energy as well. Trigeneration is also popular under the name of combined cooling, heating and power, abbreviated as CCHP. This technology incorporates all the components of a cogeneration plant plus an absorption chiller and its required accessories – the part which generates the cooling energy. Absorption chillers are one of the oldest technologies for environmentally friendly cooling.
How it works
The source of the cooling energy in trigeneration plants is actually the waste heat recovered in the cogeneration plant. Therefore no additional electricity or fuel is required for the cooling in particular, unlike other cooling technologies - electrical chillers or gas heat pumps, for example. The only electricity required for the cooling in this case is for the peripheral equipment in the absorption chiller plant, such as circulation pumps, lights, etc.
Trigeneration can be considered an upgrade of cogeneration plants from the point of view of both technology and efficiency. As a technology - because it adds more functionalities to the plant, and as efficiency - because it allows for the potential savings of even bigger quantities of electricity. Why is that? The principle of energy efficiency requires that no energy should be wasted, and all that is generated must be consumed. In addition, from engineering point of view, there must always be maintained a certain balance between the generated amounts of electricity, heating and cooling energies. Thus, if the heat of cogeneration plants is used only for space heating during the winter and for hot domestic water all over the year, the need for that in the summer is substantially lower, so the generation of electricity should be reduced too. Transforming the waste heat into cooling energy for air-conditioning will allow the engine to run at full power all over the year.
Who can use trigeneration?
Trigeneration systems are suitable for energy consumers mainly in the industrial and service sectors, which consume cooling energy for their manufacturing processes or for centralized air-conditioning of large spaces. Similar to cogeneration, there must be simultaneous need (and consumption) for more than one energy type. Trigeneration plants always generate three energy types simultaneously (electricity, heating and cooling), however, they may be designed to deliver to the consumer all of them or just two out of the three.
When the energy types are just two, the first one in cogeneration and trigeneration plants is always electricity, whereas the difference is in the second one – thermal energy in cogeneration plants, and cooling energy in trigeneration plants. The amounts and types of energy that will be delivered depend on the specific energy needs of the consumer (factory, hotel, hospital, data center, etc.) and on a number of important technical factors, which are carefully analyzed before such a system is implemented.
To understand whether you can benefit from trigeneration, start considering the following questions:
- Do you consume a lot of electricity for cooling energy?
- Do you need cooling energy all over the year or only for a few months?
- Do you need electricity and cooling simultaneously?
- If you have chillers, how efficient are they? How much do you (or would you) pay for electricity for cooling?
- Does your country buy electricity from cogeneration (trigeneration) at a preferential price (feed-in tariff)
- Does your country give subsidies for energy efficiency and reduced carbon emissions?
As this is just a starting point in the evaluation, do not hesitate to contact us for a detailed analysis and consultancy on trigeneration feasibility for your environment.