CONCEPT OF TRIGENERATION

Using GPP Business Park development as an example

GPP Business Park

is a modern office complex in which a state-of-the-art trigeneration system has been used in commercial buildings for the first time in Poland.

Trigeneration

(CCHP) involves simultaneous production of electricity, heat, and chill.

Two devices are the basis of the trigeneration system

The first is a CHP (Combined Heat and Power) module. It is a reciprocating engine powered by methane-rich fuel (natural gas).

The mechanical energy produced in the engine is transformed by a power generator (connected to the engine by a couple) into electricity with the required parameters (mostly having a voltage of 400V and frequency of 50Hz).

Every engine gets heated while working. In order to maintain an appropriate temperature, a cooling system must be used. Heat collected by the cooling system is next used to heat water in the utility hot water (UHW) system.

Hot fumes produced as a result of the burning of gaseous fuel are another source of heat generated by the CHP module. Depending on the type of the system used their temperature may range from 300 to 500°C.

Both heats collected by the engine’s cooling system and heat in hot fumes may be used to heat water for central heating (CH) and for preparing utility hot water (UHW) or, if needed, for various types of processes in which demand for heat exists.

During winter periods, hot water is used for the purposes of central heating (CH) and for preparing utility hot water (UHW).

During summer periods, produced hot water is supplied to the second main device that is part of the trigeneration system which is an absorption chiller.

Its primary advantage is very low electricity consumption, long life cycle, and the possibility of using the heat generated by the CHP module.

The primary task of the absorption chiller is the production of so-called chill water, or cold water having a properly lower temperature (7-13 degrees C). The produced chill water is next directed to the air-conditioning system that maintains appropriate comfort in the office space and the conference rooms. The use of the trigeneration system based on the CHP module and the absorption chiller does not exclude using conventional sources of energy. Just the opposite, they can be made complementary and inter-operational.

Electricity is produced in a so-called “parallel mode with the grid of a Power Distribution Company”. This means that if at any given moment the system produces more electricity than are the current needs of the complex, the surplus of such energy shall be resold to the grid.
A similar situation occurs in the opposite direction, if the building’s electricity demand is higher than the maximum electric power of the trigeneration system, a shortage of electricity shall be supplied from the grid of the Power Distribution Company.

The trigeneration system is the primary source of heat energy and chill for an office building. During peak times, any shortage of heat energy may be supplemented by conventional boiler systems, while a shortage of chill may be produced by compressors powered by electricity.

Advantages of the trigeneration system in used GPP Business Park:

  • A substantial limitation of losses related to transportation of energy carriers (production of electricity, heat, and chill is done on the site of its consumption),
  • Savings of electricity owing to the use of the absorption chiller that is powered by hot water,
  • High efficiency of energy use at some 90%,
  • Very low pollution emissions owing to the use of natural gas as fuel, 70% lower CO2 emission,
  • Possibility of a smooth switch of the system’s operational load,
  • Availability of fuel and easiness of its transportation,
  • Financial support in the form of PMŚP (Property Rights to Certificates of Origin for electricity generated in highly efficient CHP – so-called “yellow certificates”)
  • The total monthly costs of utilities (heating, chilling, water, electricity, and ventilation) are below PLN 4,00 per sq. m. of the rented space, in one-shift work – 50% savings compared to traditional solutions.