Building and project developers are all about getting a project from paper to a built reality. And they're about making money on projects. To make a profit, they have to keep an eye on the budget they've been given to work with. Something that adds cost to the project generally has to be balanced by cost saving in another area, or has to provide greater value, or it won't be considered. So how can we, as geothermal designers and contractors, install systems with no additional cost, or add enough value for a developer to consider a GCHP system for a project?
Change the building: As I've said in previous blog entries, we can't change the geology or building site...we have to work with what's there. What we can change in an effort to reduce the cost of a GCHP system is the building. We can work with the builder/design team to change internal gains from lighting, glass specifications to reduce (or increase) solar gains, ventilation strategy, take advantage of thermal energy storage, recapture waste energy, ensure the distribution system is optimized for a heat pump system, etc. To do this we have to learn to develop detailed and accurate energy models and use the energy model as a design tool...not just a compliance tool for LEED.
Consider hybrid options: If you can't justify a full GCHP system to a developer on an economic basis, possibly adding a fluid cooler or boiler to meet peak cooling or heating demands on peak days can reduce the size and cost of the GHX enough to improve the return on investment.
Consider marketing advantages of a GCHP system for developer: There may be other advantages a GCHP system has for a developer than simply "how many energy dollars it will save me". The developer of a retail shopping mall suggested numerous times during the feasibility assessment that he "could sell the cachet of geothermal". In other words, he believed he could ask tenants for higher rent because the project was "green".
Look at the big picture: Changing glass or lighting specifications, or changing the ventilation strategy may add cost to the glass, lighting or ventilation equipment...but the changes can reduce building loads and balance energy loads to the ground enough that savings in construction of the GHX will offset the cost of the changes.
Consider all GHX configuration options: Realize that a vertical GHX is not the only option available on many sites. If the building loads have been optimized there may very well be enough space on the site to build a horizontal GHX. There are many different methods of installing a horizontal GHX, including horizontal trench, slinky layout, horizontal directional drilling, horizontal plowing, etc. There may also be opportunities to take advantage of landscaping and other earth works on the site by simply laying pipe under planned earth works. Possibly there is a nearby body of water that can be taken advantage of, or an aquifer that could be used. To make the most of a site, it might be useful to design a system with two different GHX configurations.
Ultimately, most developers will make their decision to install a GCHP system based on the return on investment. It's our job as designers to find ways to reduce cost of a system and/or improve the efficiency of the system. One of the best ways to do this is to work with the owner/developer/design team and look at the project in a holistic way.
In my blog I'll be expressing my opinions about what I've the learned about ground coupled heat pump (GCHP) systems over the last 30 years. I've been very fortunate to work with many interesting people who are passionate about this technology...engineers, geologists, mechanical contractors, drillers, excavation contractors...in different parts of the world. I've learned a lot from them and will be using this forum to pass on some of the things I've learned and feel are important. Please feel free to use this information if you feel it's worthwhile...hopefully you can avoid some of the same mistakes I've learned from.
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