Shine Energy Systems Geothermal Blog

Energy Sector Council

The Kamloops Energy Fair is currently the only show we attend.  The reason is pretty simple - the attendees are a focused and relevant group.  It is a pleasure to get in to discussions with folks at these events.

We kept things simpler this year and just enjoyed having great talks with interested people.  Business is good, so we were not trying to drum up business so much as we are keeping our name out there and seeing how our industry is perceived locally.  It seems like everyone, whether you’re building new or retrofitting is interested in geothermal.  The economics are a key factor, and we understand that.  But one thing homeowners have going for them, is it is a well-established industry with strong competition.  This benefits the consumer.

I just returned from the 3rd Biennial International Geoexchange Conference and Trade Show at the UBC Okanagan campus in Kelowna, BC.

As I sit here taking a break from design work I’ve fallen behind on while away, I thought it would be good to lay out what I brought back from this conference.  The trick is I won’t look up any titles or authors from the programs unless I specifically remember them.  This is my true takeaway from the event.

LOADS…LOADS…LOADS

Ed Lohrenz hammered this point home and it was followed up the next day by BC Hydro discussing building simulation software.  There was a discussion indicating that conventional mechanical engineers have had too much liberty in using rule of thumb to quickly design systems.  This is my interpretation anyway.  But, the honeymoon is over, as there are real repercussions with associated $’s lost to over-designing systems.  Hopefully, we’ll see the conventional industry either get on board or get out of the way.  There are some highly complex software tools available to do good building energy modeling.

ERGONOMICS

Or a fancy word for simplify.  Healthyheating.com had a great discussion on the complexity the mechanical room starts to take on to the average consumer.  We need to really focus on simplifying design, standardizing equipment, and cleaning up our installation work.  Our work is a consumer product and, as such, should reflect the simplicity of use that standard household appliances have.  This was my favourite talk.

HYBRIDS

GeoExchange is just part of the solution to complex systems.  We’ve known this, but it was good to see projects on the ground reflecting this.  Not as many projects as should be out there, but then again, we need to convince engineers that business and politics are all parts of our world.  Once again, my interpretation.  Waiting for the clients’ to call on is a poor second to building our own projects.

NETWORKING

Networking is always an important part of these events and it is good to see some friends and associates.  Sharing thoughts allows one to confirm one is on track (or not).  Suppliers give a great perspective on the general health of the industry.  Competitors become partners in large projects.

GUEST SPEAKERS

Our federal Minister of Natural Resources gave a peppy talk on the government’s focus on sustainability.  But, the mention of clean coal does not escape the ears of a geoexchange audience.  BCSEA president, Guy Chauncy, followed this speach and pulled no punches.  In an Al Gore style he drove the point home on the world issues regarding global climate change.  He then threw zealous energy and optimism at the future and solutions available to us.

MISC.

• Took some information on controls back with me.
• Cleared up some concerns regarding some design software we use.
• Scheduled some projects and ordered some supplies.
• Noted the status of our associations and the current drives.
• Met some new installers and offered my design services.
• Fell behind on my design work…

No more procrastinating.

We’ve been through a few purge cart modifications over the years.  Here is where we’re at now.

A couple of things not evident in the photo:

• quick connect fittings on both lines
• 3 way valves allow us to reverse purge flow without disconnecting
• mostly brass - some galvanized only because that is what we had on hand at the time
• aluminum reservoir so no rusting
• large volume to ensure quick dilution
• drain tap near the bottom of the reservoir
• waterproof electric on/off switchbox is visible just above the filter in the 1st photo

I just spent the last two days at a Design Charrette to discuss the house design for the 2010 EQuilibrium Training House.  The goal of the 2010 house is Net Zero.  That means that it produces as much energy as it consumes.

This work is a combination of private and public sectors  and includes:

• Thompson Rivers University;
• Canadian Home Builders’ Association (CHBA) Central Interior Chapter; and the
• Canadian Mortgate and Housing Corporation.

The Kamloops “Green Dream Home” team, which includes students and faculty in TRU trade-entry and advanced technology programs, in partnership with the Home Builders, will design and build the eco-friendly home at Sun Rivers in Kamloops, and the “Green Dream Home” will once again be sold to the Kamloops Y for their 2009 Dream Home fundraising project.

Lots of win-win in a project of this scope and too many people to thank for putting in their time and effort.  For us, it was great to get a bigger scale perspective of  home energy optimization.

Another rule of thumb that seems to float around is 20% methanol (by volume) for closed-loop freeze protection.

By CSA code, we need to freeze protect the loop to 5C (9F) below our coldest design EWT.  The basic starting point for loop design would have the coldest at 0C (32F).  So we would need freeze protection to -5C(23F).  Grabbing a freezing points of methanol chart, one would see that you can achieve this level of freeze protection with 10% methanol by volume.

Want some piece of mind? Then 15% methanol by volume gets you to about -9C (16F).

The real rule of thumb is that the less antifreeze the better.  Mainly due to the antifreeze having less specific heat than pure water.

As of today, EcoEnergy grants have increased 25%.

CGC announced the press release:

 The grant for a new geoexchange installation (i.e. installing a new system where no geoexchange system existed before) has been increased from $3,500 to $4,375. The grant for the replacement (upgrade) of an existing geoexchange installation has been raised from $1,400 to $1,750. Access to the program continues to be on a first-come, first-served basis, and grants are subject to the availability of funds.

A link to a negative press article came up in a geothermal discussion forum.   If you don’t want to read the article a quick summary:

• Local council is considering banning geothermal systems on the island.
• They are concerned about their aquifer.

It is an interesting article in that it points one to a different perspective on geothermal.  It is very common for small communities on islands to be adverse to change and development period.  Their resources are limited and they moved there to get away from others (and rules) so there is often self-protection as the main motivator.

With all my biases in place, I can’t help but critique the (potential) decision somewhat.  Firstly, they’ve lumped all geothermal systems as being associated with risks to their groundwater.  Keep in mind, there is nothing that doesn’t have risk. The council was presented with the differences between open, closed, vertical, and horizontal but appear to have latched on to the risks (however negligible) associated with each.  I also wonder what the common current source of heating/cooling is?  Are gas lines, propane tanks, oil tanks, or coal burning electricity any less risk to their local groundwater? It appears it is heating oil from the paragraph below.

Councilman Peter Reich suggested limiting closed loop systems to summer operations only so that bottled water, instead of a thermally conductive fluid, could be used and would pose no risk of contaminating the aquifer. Geothermal’s efficiency is higher for air conditioning than it is for heat. Mr. Reich noted that houses with geothermal heat may use less fuel oil in the winter but that the continual pumping necessary for heat exchange increases electric use. For cooling in summer, the net electric use is lower compared to houses using standard air conditioning, he added.

Oh, I can’t help to pick this perspective apart.

suggested limiting closed loop systems to summer operations only so that bottled water, instead of a thermally conductive fluid, could be used and would pose no risk of contaminating the aquifer

Firstly, the bottle water idea.  How is that different from an open-loop re-introducing the groundwater back to its source, albeit, at a different temperature?  Other than that, sure a design could incorporate water and no antifreeze in to a closed loop system.  It just makes for an extra long ground loop, but it can be done.

Geothermal’s efficiency is higher for air conditioning than it is for heat. Mr. Reich noted that houses with geothermal heat may use less fuel oil in the winter but that the continual pumping necessary for heat exchange increases electric use.

Incorrect, geothermal efficiency is not higher for air conditioning than heating.  There are cooling load dominant heat pumps and heating load dominant heat pumps.   The comparison of electric usage and oil usage is a bit of a straw man argument in the context of this article.

For cooling in summer, the net electric use is lower compared to houses using standard air conditioning, he added.

Correct. I’ll award some points here.

So here is my suggestion to local council.  Make geothermal systems part of your local building permit requirements. Mandate only closed loop horizontal if you want.  Adapt federal guidelines in to process if you want.  And keep in mind, one oil spill entering a drinking water well will have far greater consequences than any antifreeze (methanol, ethanol, or propylene glycol) spill.

Do’s and Don’ts

I took the liberty of copying pages 19 and 20 from the UK’s Domestic Ground Source Heat Pumps: Design and installation of closed-loop systems (2007 edition). It seems like a good overall guide - though I skipped inserting the standards section as Canada has its own standards. Keep in mind some of this is already in our codes and Europe is radiant focused.  I’ve also changed a bit of the wording to reflect our actual processes.

Concept stage

Do

• Prioritise the reasons for considering a GSHP system (you can then rank the principal benefits which can be quantified during the design process). These could include:
  • Costs
    • capital costs
    • running costs
    • maintenance/servicing/inspection costs
    • lifetime costs
• Primary energy use
• Environmental impact – CO2 emissions
• Check the suitability of the local soil and geology for an effective ground loop heat exchanger.
• Check site access for equipment to install a ground heat exchanger, e.g. digger/drilling rig.
• Contact an electrician to find out the maximum load (and starting current) that can be connected to the building’s service.

Don’t

• Expect initial capital costs to be lower than that for a conventional HVAC system.

Design stage

Do

• Explore ways of minimising space heating and hot water demand by incorporating energy efficiency measures.
• Recognise that a GSHP system needs to be sized, not just to meet the peak thermal power requirements, but also to deliver the annual energy requirements sustainably. Output is limited to the amount of renewable energy that the GSHP system can collect from the surrounding ground.
• Calculate building heat losses accurately (the accurate assessment of infiltration rate is particularly important).
• Assess monthly/annual useful energy requirements based on actual anticipated occupancy and use.
• Consider providing domestic hot water (DHW) – determine usage, loads and system type.
• Consider the need for space cooling (if any) and quantify.
• Decide on the need for supplementary heating/ cooling (if any) and quantify.
• Consider the lowest temperature possible heat distribution system (the lower the heat pump output temperature the more efficient the operation of the GSHP system will be).
• Ensure that any underfloor heating system is designed for the lowest working temperatures.
• Be aware of the advantages of solid floors as opposed to timber and insulate adequately below.
• If the system does not include a buffer tank, ensure that there is adequate thermal capacity in the heating system such that run periods for the heat pump are not too short even if heating zones are switched off.
• Take care over the design of the ground heat exchanger, i.e. pipe length, diameter, configuration etc. Wrong ground heat exchanger pipe lengths and diameters are costly errors.
• Ensure that the ground heat exchanger and the heat pump are designed to operate efficiently together.
• Consider space for the spoil when planning trenches in a restricted area.

Don’t

• Guess or use rules-of-thumb for heat loss calculations.
• Assume there will be sufficient space for a horizontal ground heat exchanger without calculating the length required.

Equipment selection

Do

• Correctly size equipment (do not add a large ‘safety margin’).
• Ensure that the ground heat exchanger circulating pump is suitable for use with the circulating fluid (for example water/antifreeze) and for the operating temperatures (for example suitable for chilled water applications).
• Take care using antifreeze for the ground heat exchanger (for example the viscosity of propylene glycol increases significantly at low temperatures).
• Use high density polyethylene (HDPE) pipe for vertical ground heat exchangers, and high or medium density polyethylene pipe for horizontal ground heat exchangers. Joints should be thermally fused to exacting standards, e.g. electrofusion.
• Make sure that any domestic hot water cylinder used is suitable and has an adequately sized heat exchanger.

Don’t

• Buy a collection of unmatched components from various suppliers and expect them to work efficiently.
• Use rule-of-thumb selection for pipework and pump sizes.

Installation

Do

• Discuss the implications of the GSHP system with the main building contractor (or homeowner) so it can be included in site operations planning. Burying the ground heat exchanger is likely to be a novel activity for most builders.
• Use a reputable installation contractor (ask for and take up references, ask where the operatives were trained and how many installations they have done).
• Ensure that the ground heat exchanger is adequately pressure tested, both before and after it is inserted in the ground.
• Choose high thermal conductivity, low permeability grout for vertical borehole systems.
• Ensure that the ground heat exchanger is adequately protected from damage after installation and that its location is clearly marked.
• Use flexible connections for pipework connected to the heat pump to reduce noise transmission.
• Ensure internal ground heat exchanger pipework, fittings and pump are insulated (to chilled water specification) to limit the risk of condensation.
• Ensure the system is fully documented (including a detailed plan showing the location of the ground heat exchanger, details of the circulating fluid, pressure tests, warranties etc).
• Properly commission the system as recommended by the heat pump manufacturer.

Don’t

• Use mechanical couplings on buried pipework.

Operation
Do

• Follow start-up instructions supplied with the heat pump.
• Improve efficiency by keeping the heat pump output temperature as low as possible (consistent with maintaining comfort).
• Read the electricity meter and record consumption at regular intervals. Once a pattern of normal use has been established any unexpected increases in consumption can provide warning of a potential problem.
• Check any fitted pressure gauges periodically to make sure there is no downward trend.