Combined Heat and Power Systems

What is a CHP? It is an on site electricity generation plant, where the use of heat from the engine or the generator is taken to simultaneously generate both electricity and useful heat. CHP’s capture some or all of the by-product of heat for heating purposes which replaces your existing heat source (Boilers) therefore achieving savings.

We have been fortunate to be able to install CHP’s into some amazing premises, but it is not an Energy Management Tool that can be taken lightly. It must have serious planning and more importantly be managed going forward. We would recommend that a site survey be completed to understand any benefits from this technology.

When you look at developing a CHP Project we would recommend that a comprehensive program is developed to ensure that CHP is the right product, It is the correct application, the correct size and that it has a full life cycle service programme.

We once presented to a group of CHP Manufacturers and started our presentation with ‘A CHP is not just for Christmas’ that did raise some eyebrows but by the end of my talk they all understood that the CHP has to be manged throughout its life Cycle. In some cases, ‘Daily’ because each day the systems change.

We thought we would document the following approach to delivering a successful CHP project these are the processes we would follow to ensure it went well from start to finish.

Ask Questions:

• Is there a high heating demand on the property?
• Is there significant electricity demand on the property?
• Is there a heating process?
• Is there a Swimming Pool?
• Is there a way we can use excessive heat on the site or in the community?

If Yes to the above or some of the above…

Desktop:

Review all the existing data that is available for the property and review both the heating demands and electricity demands over a 2-year period. This will help understand possible sizing. It is worth noting here that a good understanding is put in place to ensure the history of that data is understood and what future expansion or reduction the organisation has for that property. If the Organisation is planning to reduce energy by 20% due to an Energy Management Plan look to sizing accordingly.

It is also worth understanding what the current position of the property’s kVA Availability is as there could be commercial issues with the District Networking Operator here, putting a limitation on the unit size due to exporting.

If Yes to the above …

Sales and Engineering:

This should be implemented by an application engineer in conjunction with a consultant to assess the property to identify project viability. From initial feasibility studies to comprehensive site surveys and expertly identify what is required for each specific site and to recommend a system that will meet its needs. Not only should the on-site project be considered. A complete review of how the CHP is going to be installed, arrive on to the site and even the logistics to get the CHP from the manufacturers to the property. You need to consider road closures, crane operation and in some cases the dismantling of the property just to get the CHP in place. This could all put a stop to the project as a balance must be made cost verses savings.

If Yes to the above …

Design:

In-House design team using the state-of-the-art technology to identify the logistic of implementing the CHP scheme onsite. The team need to be able to prepare detailed design drawings identifying site interfacing and plant room access considerations before the project is taken to site. Careful thought will need to be given at this stage. 

The CHP design team needs to consist of building service engineers and specialists from the field of power generation. The team also need significant experience of delivering CHP into different property portfolios.

Production:

The CHP technology needs to be manufactured to the highest standards. Using state of the art testing, with rigorous tests on performance prior to site delivery, ensuring the unit that goes to the site has already been pre commissioned.

Project Management

Project management team needs to be put in place to work with the organisation with weekly reviews, ensuring that all skill sets provide detailed information and specifications that will ensure that the CHP system is fully integrated with the building systems.

A senior engineer should be appointed to the project, with the responsibility of producing and then implementing a detailed package of information, typically consisting of:

• Project specific scope of works, design, and specification for the works.
• Programme of works
• Construction, Design and Management (CDM) paperwork
• Operation and Maintenance (O&M) manuals
• Full Handover to Maintenance

Monitoring and Management of the CHP:

During the commission stage of the CHP this where handover begins, and the site team need to be trained on the system. CHPs cannot be installed on a site without the full understanding of the on-site maintenance team. This is where independence of the manufacture works well. Explanation of the system and expectations of their daily role is critical for the day to day operation.

CHP Performance

Daily review of the CHP data is critical to keep the savings on track along with a real time monitoring system ensuring the units are delivering their expected savings. We feel here the CHPs must maintain daily kWh and Daily Hours Run. 

The graph below shows the performance of a CHP installed at a leisure centre where the CHP has not run (green trend) and where the CHP has performed well (grey trend). This should be provided as an ongoing service to ensure the CHPs runs to their maximum efficiencies.