Those of us in the ground source heat pump (GSHP) industry already know of the many benefits that these systems hold over conventional heating and cooling systems (and have probably explained them a hundred times over). But as the appeal of geothermal technology shifts to the masses, we must find ways to relate to everyday […]
When designing geothermal ground loops, this is an issue that a lot of people get hung up on. Because of the advantages of, we use parallel circuits in ground loops almost exclusively in our industry. Read more to hear why.
When loops are tied in series with one another, they will all see the full system flow rate (because there is only one flow path) and the pressure drop through the loops add together. Because there is only one flow path, the pump must overcome the pressure drop through each consecutive loop as the fluid travels through the system from the supply to the return line. The pump will be required to produce the combined pressure drop from the series loops at a shared flow rate.
In a parallel system, the flow through each loop will be the same. We add individual loop flows together to get the combined total system flow rate on the supply-return line back to the heat pump. The amount of pressure required to overcome friction losses through each loop (because they equally share the total system flow) will all be the same. The pump will be required to produce the combined flow rate from the parallel loops at a shared pressure.
To Summarize:
In a series system, the total length of the well pipes would have to be figured in calculating head loss while in a parallel system only one loop needs to be calculated.
Parallel flow: Individual loop flow rate adds at a common pressure drop
Series flow: Individual loop pressure drop adds at a common flow rate
Series system
Advantages include: Single flow path and pipe size, higher thermal performance per foot of pipe, since a larger diameter pipe is required.
Disadvantages include: Larger water or antifreeze volume of larger pipe, higher price per foot of piping material, increased installed labor cost, limited length due to fluid pressure drop and pumping costs.
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Here is an excerpt from a white paper I just published on how and where a ground source heat pump can be utilized to gain LEED certification.
By now, nearly everyone has at least heard of LEED but not many understand what it means to be LEED-certified or how best to earn certification. Developed by the US Green Building Council (USGBC), LEED stands for “Leadership in Energy and Environmental Design”. Simply put, LEED is a grading system for sustainable building design and construction.
The goal of the program is to encourage the construction of buildings that use less energy, water and natural resources in order to minimize the impact of a structure on the local environment during construction and throughout its useful life. Needless to say, geothermal heating and cooling systems can go a long way to supporting all of these goals.
The LEED rating system works by requiring a minimum level of performance through prerequisites organized under eight different categories. Once you are able to meet the minimum performance requirements in each category, any improvements above and beyond are rewarded through a points system. The eight categories are:
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This is the last part in a three part serious about the three most common errors that geothermal designers make when designing ground source heat pumps system. If you’ve been following, the main concern for a very simple reason, the geothermal industry is small but quickly growing so it’ll be best to minimize any black eyes from poor system design.
In my last two posts, I’ve outlined the first two big mistake made by designers.
Underestimating the importance of accurate peak heating and cooling load calculations
Not Giving Proper Consideration to Alternatives posted on Heating Help.com
The third mistake is simple, don’t overcomplicate the design.
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If you’re new to the geothermal heat pump industry, read the Geothermal 101 Reading list. It has free tools and articles on geothermal design and installation, and sales and marketing best practices.
Working in the ground source heat pump (GSHP) industry, especially in a small company where you are asked to take on the role of salesman and designer, you will find yourself answering the same questions with each new customer. Get used to it. If you work in the industry long enough, you will be asked every question under the sun. How will this system heat my home when the soil temperatures are only 50 degrees? What if I want to keep it warmer in my house? Do I need to buy an air conditioner too? How does a heat pump work? The list goes on and on.
The truth is, the average homeowner doesn’t understand how their central air conditioner works (or the refrigerator in their kitchen for that matter). They just know it works. When you mention the term “geothermal heat pump” or “ground source heat pump” to your prospective customer, all of a sudden you find yourself in uncharted territory. Then the questions begin.
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