Renewable Energy and Heat Pumps – Net Zero Energy by Design

As a mechanical engineer I spent 17 years in design of mechanical systems. Always seeking the best solution given budgets and adhering to efficient design principles. Often we can combine systems by hybridization, where two technologies come together in a synergistic match. I have used hybrid technologies, using ground loops and air-air fluid coolers, with heat pumps successfully in the mechanical design and construction of a number of buildings.

While wind energy may be harvested, it is not always available. Some regions get more wind than others, and there may be governmental or civic restrictions. For renewable energy, solar may be a better option than wind, even though it is only available during the day. In either case some form of auxiliary power will be required, such as batteries,  grid connection, fuel powered generator, or hydro-power.

The use of heat pumps allows for the provision of a number of heating and cooling devices which may be connected to a central circulating building loop. As heat pumps have operating temperatures generally between 40F to 90F, although it may vary depending on heat energy source, such as air, water or ground.  Air temperatures may vary during the day and season. As air temperature drops, heat pumps lose efficiency. We can see this in the following figure. (1)

air-source-heat-pumps-cold-weather

In the case of geothermal heat pump system design, there are some options. One method is to run a water source such as a pond, river, body of water in an open loop design,  in a closed loop method using an process waste heat stream or ground coupled system. Either system is usually connected to a heat-exchanger to which is connected a second closed house loop. The house loop is controlled to either discharge or gain heat from the geothermal loop.

I am attaching  a blog post (2) from 2007 where I made a comment in 2009. This blog post is still getting comments. I believe such systems can be designed and constructed and would contribute to a “Net-Zero” building systems.

I am a lawyer who has been interested in the subject of energy conservation since the seventies. Back when we had the first OPEC crisis, I thought this country would head in a direction away from the consumption of huge quantities of oil and gas. It didn’t happen. Now of course, our thirst for oil has been the primary reason for a preemptive war with no end in sight. Moreover, peak oil seems to be here. And so far nothing much seems to have changed. But the public, may at last be ready for something different.

There are some real promising things happening with new solar energy systems and with wind turbines. It is long past due. But I still keep wondering whether we are approaching this problem of solving our energy demands the right way. With both solar and wind systems all technology seems to be headed toward the creation of electricity. Electricity is definitely useful but often inefficient.

Heating and cooling costs are about 60-70 percent of home energy costs. It is far more cost effective to use heat transfer than to make heat. Water source heat pumps are 300-400 percent efficient while the best ordinary HVAC systems might be forty percent efficient. (Are they that much?) What if you could even vastly surpass the efficiency of a water source heat pump. How? By making the wind pump the water instead of an electric pump.

Why not use wind to its best advantage? Make the wind do what it has done very efficiently for hundreds of years: pump water. Make it pump water from a warm place to a cold place and make it store the heat where the heat is needed or wanted. In the winter pump the heat from under the ground into the house. In the summer pump the heat from house into the ground.

To do this, because of the wind’s variability, one would need a huge (?) thermal sink in the house to slowly release the heat transferred from underground to the heat sink or to transfer the heat from the house to the ground while the wind was not blowing.

A four part system. A wind turbine. A pump. A closed loop of pipe. An interior thermal sink.

It is fairly well known that in most climates, five or six feet below ground, the temperature is a about 55 degrees. I think it is quite possible to take advantage of the geothermal underground temperature by using a wind turbine to pump water from underground into an interior thermal sink. If a large enough volume of water could be circulated to where the interior heat sink reached 55 degrees, I think such a home’s heating and cooling costs would be drastically reduced.

If the large thermal sink could get the house temperature substantially raised in the winter and substantially cooled in the summer, very little additional energy might be required to bring it to a desirable temperature with the use of a water source heat pump. A water source heat pump would work in tandem very well by using the internal heat sink as a convenient source to operate a water source heat pump.

My idea would be to use a vertical wind turbine on the roof coupled to an Archimedes screw to pumps and circulates water through the closed loop. The vertical wind turbines seem to need less wind, have more torque, and are quieter. I also think that from an architectural point of view, they would look much more attractive, especially the ones that look like spinnerets. They also take advantage of a sloping roof which increases wind speed.

I also think the Archimedes screw would be an ideal pump. It requires no gears or lubrication and could attach by a straight shaft to the vertical wind turbine. An Archimedes screw would be very inexpensive as pumping systems go and extremely reliable as there is really nothing to break.

I have other ideas about roof design and about turbine design for greater efficiency. I also have ideas about the plumbing. What I would like to see is whether there are people out there who think this idea has commercial merit and if so, how we might go about making wind driven water pumping for geothermal transfer a success. We would need some engineering and architectural expertise and some ability to fabricate the wind turbines and pumps.

I look forward to responses.

Duane Tilden said…

I have been looking at the latest responses and it seems to me there is some confusion about this idea.

Firstly, heat pump technology, as pointed out achieves it’s high COP’s from the phase change. It is through the leveraging of the refrigerant phase change from a fluid to the gas phase where heat energy can be obtained from low temperature heat sources. This is how geothermal heat pumps can obtain heat energy from relatively low temp sources such as the ground where nominal ambient water temp would be at 55F and deliver hot water at temps of 90F to 140F.

Alternatively heat pumps can be used in air/air, air/water, water/air and water/water configurations. These are generally stand alone devices where in a properly engineered installation do not require supplemental heat sources.

Wind energy is a separate sustainable, environmentally friendly application. In my opinion the OP’s idea of using wind energy to move water around for a heat pump application is marginal and likely too capital intensive to realize any real benefit. Also, it is just too restrictive, in my opinion.

Wind energy converted directly to electricity, or other dedicated pumping applications where electricity is not available is best (water pumping up to a reservoir in agricultural or power generation schemes for example). There also may be some merit to the idea of storing the energy as compressed air, but the amount of heat generated would not be significant, usable heat source. Try heating your home with a candle.

Electricity is used by a wide range of applications, so why not use the wind energy to best effectiveness? The operation of the compressor in the heat pump and the pumps to run the water loop(s) require electricity, so do common home appliances.

There may be some applications where the proffered idea would make sense, but not likely widely applicable for single family residences unless you have a large property and money to burn.

SEPTEMBER 26, 2009 AT 10:44 PM

 

References:

  1. heat-pump-effective-temperature-range/
  2. wind-turbine-heat-pump-geothermal
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Transitioning Oil & Gas Wells to Renewable Geothermal Energy

Infinity Turbine 2016 ROT IT50

Figure 1:  Radial Outflow Turbine Generator – Organic Rankine Cycle – ORC Turbine (1)

Existing oil and gas wells offer access to untapped sources of heat which can be converted to electricity or used for other energy intensive purposes.  This includes many abandoned wells, which can be reactivated as power sources.  These wells, in many cases “stranded assets” have been drilled, explored, and have roads built for access.  This makes re-utilization of existing infrastructure cost-effective while minimizing harm to the environment associated with exploration.

In a recently published article in Alberta Oil, an oil & gas industry magazine they point out many of the benefits of converting existing and abandoned wells to geothermal energy.

A recent Continental Resources-University of North Dakota project in the Williston Basin is producing 250 kW of power from two water source wells. The units fit into two shipping containers, and costs US$250,000. This type of micro-generation is prospective in Alberta, and a handful of areas also have potential for multi-MW baseload power production.

In addition to producing power, we can use heat for farming, greenhouses, pasteurization, vegetable drying, brewing and curing engineered hardwood. Imagine what Alberta’s famously innovative farmers and landowners would accomplish if they were given the option to use heat produced from old wells on their properties. Northern communities, where a great many oil and gas wells are drilled nearby, can perhaps reap the most benefits of all. Geothermal can reduce reliance on diesel fuel, and provide food security via wellhead-sourced, geothermally heated, local greenhouse produce. (2)

Water can be recirculated by pumps to extract heat from the earth, and through heat exchangers be used as a source of energy for various forms of machines designed to convert low grade waste heat into electricity.  The Stirling Cycle engine is one such mechanical device which can be operated with low grade heat.  However recent developments in the Organic Rankine Cycle (ORC) engine seem to hold the greatest promise for conversion of heat to electricity in these installations.

In a “boom or bust” industry subject to the cycles of supply and demand coupling a new source of renewable energy to resource extraction makes sense on many fronts.  It could be an economic stimulus not only to the province of Alberta, but throughout the world where oil and gas infrastructure exists, offering new jobs and alternative local power sources readily available.

References:

(1)  http://www.infinityturbine.com/

(2)  http://www.albertaoilmagazine.com/2016/10/geothermal-industry-wants-abandoned-wells/

Related Blog Posts:

  1. https://duanetilden.com/2016/01/14/alberta-energy-production-and-a-renewable-future/
  2. https://duanetilden.com/2014/12/21/renewable-geothermal-power-with-oil-and-gas-coproduction-technology-may-be-feasible/
  3. https://duanetilden.com/2015/07/25/a-new-era-for-geothermal-energy-in-alberta/
  4. https://duanetilden.com/2015/07/27/oil-well-waste-water-used-to-generate-geothermal-power/
  5. https://duanetilden.com/2013/10/29/supercritical-co2-refines-cogeneration-for-industry/

Alberta Energy Production And A Renewable Future

Author:  Duane M. Tilden, P.Eng  (January 14th, 2016)

Abstract:  Energy sources and pricing are hot topics world-wide with the Climate Change agenda leading the way.  Last year at the 2015 Paris Climate Conference long-term goal of emissions neutrality was established to be by as soon as 2050.  Alberta currently produces more atmospheric carbon emissions and other pollutants than any other Province in Canada, and in order to meet clean air objectives the energy sectors which consume & mine the natural resources of the Province will have to shift to non-polluting & renewable energy sources and be more efficient in energy utilization.  To achieve these goals new infrastructure will have to be built which will have the likely consequences of raising energy pricing as well as alter consumption rates and patterns.

Transportation

Transportation is a vital link in modern society, and often a personal vehicle is chosen as the main mode of mobility to work, leisure, & social purposes.  Cars and trucks also provide means of work and commerce & are essential to our way of life.  Most of these vehicles are fueled by gasoline, some by diesel, propane, and more recently the electric vehicle (EV) and hybrids.

 

GraphData Gas Price Comparison Canada

Graph #1:  Average Cost Comparison of Gasoline in Major Canadian Cities

In Alberta, using Calgary as a basis for comparison, it is apparent that pricing to consumers for gasoline is below nation-wide market averages when measured Province by Province, as demonstrated in Graph #1 (1). While if you live in Vancouver the cost is considerably higher, due to included carbon taxes and a transit levy among additional charges.  Additional means of moving growing populations efficiently have been seen by the development of LRT mass transit for the rapid movement of citizens to work, school, or social events.

Rapidly moving the large segments of the population in a cost effective manner is important to growth.  Buses are an important link in this mix as are cycling routes, green-ways and parks.  Changes in fuels for trucks, buses and trains by converting from diesel fuel to LNG will also provide for reductions in emissions while providing economic opportunity for utilization of the existing plentiful resource.  While EV’s show promise, the battery technologies for energy storage need further development.

Alberta Electricity Production

Alberta still relies on out-dated coal plants to generate electricity.  According to a CBC article coal provides power to 55% of homes in Alberta, and is the second largest contributor to emissions (2) and GHG’s to the Oil Sands projects.  However, it has been noted that the utility is reluctant to decommission recently constructed coal plants, until they have earned back (or are compensated for) their investment in capital costs.

local-input-wabamun-alberta-march-21-2014-a-giant-drag1

Photo #1:  Highvale coal mine to feed the nearby Sundance power plant (3)  

Photo credit:  John Lucas / Edmonton Journal

There are power purchase agreements in place, which may extend 50 to 60 years from the construction date of the plant (2).  It may be possible that the coal fired power plants could be converted to burn natural gas, which Alberta has in abundance, rather than be decommissioned.  However, this would still require the closure of the coal mines and mining operations currently supplying the existing power plants.  Also, combustion of natural gas will still release GHG’s into the atmosphere, while less than coal, they are not a total elimination of emissions.

Residential Energy Consumption

When comparing monthly residential electrical energy costs across Canada, using data obtained from a survey performed by Manitoba Hydro, we see that Edmonton and Calgary are in the lower middle range of pricing (4).  Variances in all regions will occur based on average home size, building codes and insulation requirements, heating system types and other factors.  Some homes may be heated with electric baseboard which will result in a higher electric bill while other homes may be heated using natural gas as a fuel.  Also household hot water generation can be by electric or gas-fired heater, so consumption of natural gas must be considered with electrical power usage to get a complete picture of energy consumption.

residential_1000kWhresidential_2000kWh

Charts #1 & 2:  Average Monthly Cost For Residential Electricity in Major Canadian Cities For Equivalent Usage in kWh (4)

Inspecting these charts it is proposed that a price increase of 10 to 20% to Alberta electrical energy consumers by a separate tax or fee to pay for a shift in technology would be reasonable when compared to other Canadian Cities.   Additional tariffs on natural gas consumption would also be recommended.  Such an increase would likely have a secondary benefit of creating an incentive for energy efficiency upgrades by home owners such as increased insulation, better windows and heating system upgrades. Such improvements would in turn lead to reduced demand at the source and thus to lower GHG & particulate emissions to the atmosphere.

Climate and the Proposed Energy Code

Energy consumption in populations is normalized in a number of ways, generally defined by habits and patterns.  We observe that in traffic as volumes increase early in the morning as commuters travel to work, and in the opposite direction as they head home in the evening.  Often people will attempt to “beat the traffic”.  This is an admirable goal in energy usage as well, for consumption of electricity will follow other such predictable patterns as people eat meals, shower, and perform other rituals that interface with electrical,  heating,  ventilating, elevators, water supply and disposal systems that form infrastructure and services provided by municipalities and utilities.

As these systems need to be energized and maintained, it is desirable to be able to predict and control the consumption and distribution of resources.  The greater of these is the electrical generation and distribution system.   Also, emerging technological advancements in energy efficiency such as CFL, LCD displays, computers, refrigeration, energy storage and more.  Advancements in co-generation, district energy systems, and other end use distribution of energy which provide economies of scale are also possible as strategies to obtain goals.Heating Degree Days - Lower Western Canada

Map #1:  Partial Map of Heating Degree Days for South-Western Canada (5)

Opportunities will exist for building mechanical system enhancements and upgrades as they may provide energy savings and cost reductions to users often calculated with a minimum nominal payback period of 5 to 7 years (and should be determined in every case).   The HDD map can provide a source of information which is used in energy models to determine predicted building energy costs when calculating payback periods to justify system upgrades or design decisions.  Obtaining and monitoring building energy consumption rates and year over year changes are important resources in determining where systems are running at below optimal rates and require replacement.

In new building construction the National Energy Code for Buildings 2011 (NECB) (6) has been adopted by Alberta (7) for all municipalities.  As there are higher HDD values attributed to Calgary and Edmonton as seen in the HDD Map of Western Canada, a requirement for stringent construction methods and materials to higher standards ensure new buildings meet carbon emissions reduction goals.

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Photo #2:  Construction of Towers in Calgary with High Window to Wall Ratios 

Photo Credit: Duane Tilden P.Eng

Increased requirements in glass U-values and shading coefficients, maximum window to wall ratios (WWR) to reduce undesirable solar heat gain and heat losses, energy consumption and improve occupant comfort.  Buildings with excessive glazing are difficult to heat and cool, requiring sophisticated mechanical systems to offset poor performance by the building envelope.

Code mandated higher insulation values & better materials; moisture and heat control of the envelope through better design.  Higher efficiency requirements for mechanical systems; (fans & ducts, pumps & pipes, and wires & motors), lighting, controls, and other components of the building and it’s envelope.  Energy modeling should be performed of larger significant buildings to optimize operations in the design phase.  Commissioning of the building is integral to ensuring compliance throughout the project to it’s final phases at substantial completion and occupancy.

Renewable Energy

Renewable energy technologies including solar power and wind generation  have been gaining rapid adoption elsewhere in the world, while in Alberta (8) carbon based fuels currently provide over 80% of electrical power generation.   This has not been for a lack of wind and solar resources in Alberta but to be attributed to the large capital investments in fossil fuel resource extraction.  Other renewable technologies such as bio-mass, hydro, and geothermal may also be employed and should be investigated as alternatives to existing thermo-electric power plants.

Alberta Energy Sources - 2015

Table #1:  Installed Electrical Generating Capacity by Fuel Source in Alberta (8)

Currently, Alberta has the third highest installed wind power capacity in Canada behind Ontario and Quebec.  Wind energy not only represents a means to green the power production, it also will contribute jobs and income to the economy.  As one source of electricity and revenues is removed another source will fill the void.

installed_capacity_e-4

Map #2:  Installed Wind Power Capacity by Province in Canada (9)

While significant inroads have been made in Alberta for wind power which is already established as a major power source for the future, there is unrealized potential for the installation of solar power production.  It has been noted that a photo-voltaic installation in Calgary is 52% more efficient than one installed in Berlin, Germany.  Meanwhile, Germany has 18,000 times more solar power generation capacity than installed in Alberta (10).

alberta-germanytiltweb

Map #4:  Solar Resource Comparison for Alberta & Germany (10)

Alberta has significant solar resources, even during the winter when daylight hours are shorter. Lower temperatures improve PV efficiency, and properly tilted south facing panels optimize light capture, while the flat terrain of the prairies provide unobstructed maximum daylight.  Light reflection by snow on the ground would further enhance light intensity during the colder months.  Thus solar represents a relatively untapped potential source of significant electrical power for Alberta and an unrealized economic opportunity for consumers and industry.

hotspots_13

hotspots_leg

Map #5:  Solar Resource Map for Canada With Hotspots (11)

Energy Efficiency, Smart Grid & Technological Advancements

Renewable energy produces electricity from natural resources without generating carbon and particulate emissions.  Another method of controlling emissions is to reduce the amount of energy consumed by being more efficient with the energy we already produce.   We can achieve this by using higher efficiency equipment, changing consumer patterns of use to non-peak periods, use of Smart Meter’s to monitor consumer usage and to alert homeowners when there is a problem with high consumption which could result in higher bills than normal if the problem remained unreported.

There are other advancements in the electrical grid system which are on the horizon which will enable a utility maximize resources by such means as energy storage, micro-grids, demand response to name a few.  Also, property owners and businesses could be able to grid-tie private solar panel (PV) and storage systems to supplement the utilities electrical system with additional power during the day.

Summary

In order to meet the goal of atmospheric emissions neutrality as agreed to at the 2015 Paris Climate Conference Alberta is posed with making decisions on how electricity is to be produced in the future.  Eliminating coal power plants and replacing them with Renewable Energy power sources such as solar and wind power are proven methods to reducing GHG and particulate emissions as these power sources do not involve combustion and discharge of waste gases formed during the combustion process.  Coal combustion is well documented as a major contributor of GHG’s to the atmosphere.

To make the transition will require capital for financing to build new infrastructure.  Funding of these projects should be raised proportionally charged to users with increased rates.  These rate increases will provide further incentives to reducing energy consumption and thus air emissions.  Jobs will shift and employment will be created in new forms as the old is phased out and replaced with new technology.  These new systems will have to be designed, built and maintained while the workforce will require training in new methods.  There will be many new opportunities for growth and advancement resulting from the implementation of these changes to meet Canada’s International commitments.

References:

  1. http://www.nrcan.gc.ca/energy/fuel-prices/4593
  2. http://www.cbc.ca/news/business/coal-compensation-power-alberta-1.3321467
  3. http://edmontonjournal.com/business/local-business/albertas-commitment-to-phase-out-coal-fired-power-sparks-fears-of-job-losses
  4. https://www.hydro.mb.ca/regulatory_affairs/energy_rates/electricity/utility_rate_comp.shtml
  5. http://ftp2.cits.rncan.gc.ca/pub/geott/atlas/archives/english/5thedition/environment/climate/mcr4033.jpg
  6. http://www.nrc-cnrc.gc.ca/eng/publications/codes_centre/necb_2011_adaptation_guidelines.html
  7. http://www.municipalaffairs.alberta.ca/CP_Energy_Codes_Information
  8. http://www.energy.alberta.ca/electricity/682.asp
  9. http://canwea.ca/wind-energy/installed-capacity/
  10. http://www.greenenergyfutures.ca/blog/sunny-days-ahead-solar-alberta
  11. http://pv.nrcan.gc.ca/index.php?lang=e&m=r