GEOptimize
  • HOME
  • About
  • Training
    • CGD Courses Online
    • CGD Courses in your Office
    • CGD at IGSHPA
    • Register
  • Services
    • Feasibility
    • Residential
    • Geo Forensics
    • Peer Review
    • Design Assistance
    • GCHP & GHX design
    • Manage your GHX
  • Products
    • Ground Loop Design >
      • GLD quote
    • GeoCube
  • Projects
    • Agriculture
    • Commercial >
      • Steinbach Credit Union
      • Walkerton CWC
      • 2211 West 4th
    • District Systems >
      • Gibsons, BC
      • Seasons of Tuxedo
      • Miami, MB
    • Institutional >
      • Prairie Dale School
      • St. Pierre Church
      • College Universitaire St. Boniface
    • Multi-family Residential >
      • Bethany Manor
      • YWCA Elm Centre
    • Recreational >
      • Port Hawkesbury Civic Centre
    • Retail >
      • Neechi Commons
      • IKEA, Centennial, CO
  • Blog
  • HOME
  • About
  • Training
    • CGD Courses Online
    • CGD Courses in your Office
    • CGD at IGSHPA
    • Register
  • Services
    • Feasibility
    • Residential
    • Geo Forensics
    • Peer Review
    • Design Assistance
    • GCHP & GHX design
    • Manage your GHX
  • Products
    • Ground Loop Design >
      • GLD quote
    • GeoCube
  • Projects
    • Agriculture
    • Commercial >
      • Steinbach Credit Union
      • Walkerton CWC
      • 2211 West 4th
    • District Systems >
      • Gibsons, BC
      • Seasons of Tuxedo
      • Miami, MB
    • Institutional >
      • Prairie Dale School
      • St. Pierre Church
      • College Universitaire St. Boniface
    • Multi-family Residential >
      • Bethany Manor
      • YWCA Elm Centre
    • Recreational >
      • Port Hawkesbury Civic Centre
    • Retail >
      • Neechi Commons
      • IKEA, Centennial, CO
  • Blog
Search by typing & pressing enter

YOUR CART

9/6/2013

If my building is already efficient will a GCHP system be worthwhile?

You might have been told that if your building is already well insulated and energy efficient there's not much point in considering a GCHP system. There simply wouldn't be a payback because of the cost of installing a GCHP system and GHX is so high that I'd never get a return on my investment.  I'd like to dispel that myth!
One of the problems in the geothermal heat pump industry is that too often designers and contractors use "rules of thumb". There are projects that have been designed and specified for contractors to bid on simply using rules of thumb. Let's look at an example using a 50,000 square foot (4,650 m2) building:
  • Heat loss = 50,000 square feet x 25 Btu/hr = 1,250,000 Btu/hr (366 kW)
  • Cooling load = 50,000 / 350 square feet / ton = 143 tons (502 kW)
  • Borehole required = 143 tons x 180' / ton = 25,740' of drilling
  • Borehole configuration should be 1 borehole / ton = 144 borehole (round up to a non-prime number) x 180'

Great...12 boreholes per supply & return runout pair x 12 pairs of 2" runouts and there's your design. Done!! On to the next one, right?

The sad truth is that, many times, such a system, if it's not too expensive to install, will work, and it may even work reasonably well 80% or 90% of the time. But if the building is well designed, and the GCHP and GHX designer uses detailed energy modeling as a design tool, it is likely that actual building loads are much different than the rules of thumb would guess at. This means the capacity of the heat pumps needed will be much lower than rule of thumb estimates, and implications on the size of the GHX can be enormous. 

And if the designer has an opportunity to work closely with the owner and his or her design team, using the energy model as a design tool it's possible in most projects to reduce the size of the heat pump system and the size and cost of the GHX, while creating a more efficient, robust system. This can have a large impact on the return on the owners investment.

To answer the question about the return on investment in a very efficient building: It an be a very appropriate system and provide a very solid ROI IF the designer takes the time to go through the design process needed to design a GCHP system and GHX. 

The Certified GeoExchange Designer (CGD) commercial geothermal system design course offered by IGSHPA and AEE is a 3 day course that goes over in considerable detail the design process that is needed to optimize the design and performance of a GCHP system. 

An example of the impact this approach can be seen in a presentation at the QUEST Conference in Winnipeg, November 2012

Comments are closed.


    Ed Lohrenz

    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.

    Archives

    September 2021
    November 2016
    January 2016
    April 2015
    February 2015
    January 2015
    October 2014
    September 2014
    April 2014
    February 2014
    January 2014
    December 2013
    November 2013
    October 2013
    September 2013
    August 2013




    Categories

    All Building Design Energy Storage Energy Supply Energy Use Ground Heat Exchangers Incentives Industry Events Interesting Systems Monitoring Your System Product Info Standards System Design Training Workshops Waste Heat Recovery

    RSS Feed



HOME
ABOUT







Privacy Policy 
TRAINING
      CGD Courses Online

      CGD Custom Courses
      CGD at IGSHPA

SERVICES
  Feasibility
  Geo Forensics
  Peer Review
  Design Assistance
  GCHP & GHX Design
  Manage your GHX
PROJECTS
   Agriculture
   Commercial
   District Systems
   Health Care
   Industrial
   Institutional
   Multi-family Residential
   Recreational
   Retail
BLOG

GEOptimize Inc.                 220 Portage Avenue, unit 1410, Winnipeg, MB, R3C 0A5, Canada               +1  204-318-2156