The main advantage of the packaged CHP system is that the unit can be manufactured and prepared at the supplier’s premises and then delivered to site ready for offloading and positioning.
Most CHP packages are designed and supplied as complete units, selected to meet the Reliability & Availability requirements of the site and its energy demands. The package contains a Prime mover (either Gas Engine, Small Gas Turbine, or Fuel Cell), the generator and heat recovery equipment, together with all the associated pipework, valves, controls etc. The equipment is mounted on a steel structure, and surrounded by an enclosure, which reduces noise levels in the adjacent area. The enclosure normally contains a control panel, which is accessible from outside the package. It can also usually be easily dismantled to provide access for maintenance purposes. Typical sizes and weights for packaged CHP units are given in the table below:
Table of typical sizes and weights for packaged CHP units
| Gas-engine CHP|| Small-scale gas turbine CHP|
|Electrical output||60kW||100kW||300kW ||600kW ||1,000kW ||60kW ||100kW |
|Heat output||115kW||130kW ||430kW ||880kW ||1,300kW ||100kW||150kW |
|Fuel consumption||215kW||310kW ||990kW ||1,950kW ||3,000kW ||280kW ||350kW |
|Package length (metres)||2.9||2.9 ||4.0 ||6.5 ||8.0 ||2.0 ||2.9 |
|Package width (metres)||0.8 ||1.3 ||2.0 ||3.5 ||4.0 ||0.9 ||0.9 |
|Package height (metres)||1.8 ||1.95 ||2.4 ||2.6 ||3.5 ||1.6 ||1.9 |
|Package weight (tonnes)||2.5 ||4.0 ||8.0 ||12.0 ||16.0 ||1.0 ||2.0 |
The preparatory works for installing a CHP package are not complicated, and the main requirements are as follows:
- An area of ground on which the unit can be located. This area must be able to accept the imposed loads of the unit, and must be sufficiently accessible for delivery and positioning. There should always be adequate free space around the package to provide access for maintenance purposes. Furthermore, it is common practice to locate CHP packages within a building to avoid exposure to external weather conditions and provide easy access to services.
- A piped supply of gaseous fuel for connection to the CHP package. This normally requires a pipework connection, which can be either located in a covered access duct within the floor surface or attached to pipe supports and routed at high level within the building.
- Electrical cabling to connect the CHP package to an appropriate part of the site’s electrical distribution system.
- An exhaust system to remove the exhaust gases from the engine or turbine to a point of discharge outside the building area.
- Access to the site hot water supply system.
- Suitable means to link to externally located heat rejection equipment.
Most packaged CHP applications supply heat via a hot water connection to a site distribution system, which takes the heat to its point of use. Some applications use an airflow to cool the engine or turbine and this heated air is then available for use on-site. Furthermore, some units pass their exhaust gases directly to the site for heating purposes, either separately or mixed with a heated airflow. Packages can also be designed to vary their heat outputs between air and water, according to variations in site demand.
Next: Site Installation