Alba Technology Park

A high-efficiency energy system at Alba Technology Park in Cerdanyola del Vallès (Barcelona), which covers 340 hectares, produces electricity, heating and cooling. In this trigeneration system, energy is produced mainly by the natural gas cogeneration engines and the two high-efficiency absorption chillers that supply the district heating and cooling network connected to the Science and Technology Park, the core of the Alba Park.

The ST-4 trigeneration plant supplies electricity, hot water and chilled water to the ALBA third-generation synchrotron facility and the technology park buildings through a four-pipe district heating and cooling network.

ST-4 trigeneration plant

This installation, which produces electricity, hot water and chilled water simultaneously, offers a service of exceptional quality and reliability and is therefore the main energy supplier for the Alba synchrotron. Generating energy close to the point of supply avoids the significant energy losses of traditional systems during transport from large power plants to the points of use. In addition, the installation can meet a large part of the demand for hot water and chilled water using waste energy produced during electricity generation.

Local energy generation and distribution allows much higher levels of energy efficiency, above 86 %, well above the levels achieved with traditional systems. This system reduces the use of primary energy sources and cuts CO₂ emissions by 27 %.
The main components installed in the plant are:

• 3 cogeneration engines of 3.35 MW each.
• 2 absorption chillers: 1 Thermax ED 80C CX double-effect absorption chiller and 1 Thermax LT-105T single-effect absorption chiller.
• 1 natural gas boiler.
• 1 electric compression chiller.
• 1 chilled water storage tank that allows the plant to store energy.
• 1 cooling tower.

Electricity and hot water production

Natural gas engines produce electricity and thermal energy, in the form of hot water and exhaust gas, to meet the heating and/or cooling demand using the Thermax absorption chillers. The high efficiency of the cogeneration engines guarantees maximum efficiency.
The ST-4 trigeneration plant currently has three cogeneration engines, each with a rated electrical output of 3.35 MW and 3.10 MW of thermal energy recovery. The engines’ electrical efficiency is 45 % and the total efficiency of the system reaches 86.5 %.

Chilled water production

The heat generated by the cogeneration engines is used to produce chilled water with absorption chillers. Two chillers are installed in the ST-4 plant: a double-effect unit driven directly by the engines’ exhaust gases and a single-effect unit driven by the hot water from the engines’ cooling circuit.

Double-effect absorption chiller driven directly by exhaust gas

The Thermax ED 80C CX absorption chiller has a nominal cooling capacity of 5.1 MW and is driven directly by the combustion gases from the cogeneration engines. This type of chiller is highly efficient, with a COP of more than 1.3 on the energy supplied.

Single-effect absorption chiller driven by hot water

The Thermax LT 105T absorption chiller has a nominal cooling capacity of 3,275 kW and is driven by hot water at between 95 ºC and 78 ºC from the jacket cooling circuit of the three cogeneration engines. Its COP is 0.75, a very high value for a single-effect chiller.

Control system

The installation has a comprehensive control system that ensures the reliability and safety of the whole plant. The mass flow and temperature of all inlets and outlets are monitored to check the performance of each machine in real time.

The control system calculates the production of electricity, heating and cooling individually and/or overall. Primary energy consumption and overall efficiency are also calculated for the whole plant, centrally and individually.