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How To Combine Solar and Geothermal Energy Sources?

April 19, 2019

We discuss a lot about solar energy and why not? Currently, it is the only hope for humanity in terms of energy resources. But is unfair to not discuss other renewable energies. Yes, other renewables are currently not as human-friendly as solar energy but they are surely making progress. When it comes to switching to renewables, homeowners always prefer solar energy panels. They are effective when powering appliances like fan, TV, cooler and other household appliances. Heating, on the other hand, requires additional energy which is beyond the capacity of solar energy panels a homeowner has installed.

So instead of making a substantial investment to add additional power generator in your solar panels, you have alternatives. One such alternative is Geothermal energy. When you pair a geothermal system with your solar energy panels, you could enjoy the benefits of both. A combined system has a variety of advantages which cannot be harnessed individually.

Before we begin telling you how you can combine these two systems, lets first understand what is geothermal energy.

What is Geothermal Energy?

In layman’s term, geothermal energy is the heat from the earth. It’s clean and renewable. Resources of geothermal energy range from shallow groundwater to hot water and hard rocks found at the bottom of the earth’s crust.

Hot dry rocks occur at a depth of 5000m to 8000m everywhere beneath the earth’s surface and at lesser depths at certain areas. Access to these resources involves injecting cold water down one well and circulating it around the hot rocks and pumping out hot water from another well. 

What is Geothermal Heat Pump?

Geothermal heat pumps (GHP’s) also known as ground-source heat pumps can be used to circulate both hot and cold water to or from the ground.

Geothermal pumps can be used irrespective of weather condition because of the earth’s constant temperature below the earth’s surface. 

Why Homeowners Should Combine Solar and Geothermal system?

A geothermal heat pump circulates cold water through the pipes deep below the ground. The liquid absorbs heat from the hot fractured rocks and returns to the pump at the surface level. Allowing you to obtain a clean, renewable and eco-friendly source of energy. But one disadvantage of the geothermal pump is that it runs on electricity and therefore we cannot call it a 100% eco-friendly option.

But if you coupled a geothermal pump with the solar PV system, your solar panels could generate electricity for your geothermal heat pump at a relatively lower cost. When these two systems work coherently, a homeowner can reach new heights of efficiency, reducing both the environmental impact and energy expenses.

In terms of energy savings , this combined system will save almost 80% of energy on hot water, cold water and air-conditioning. Recent advancement in solar and geothermal technologies has given birth to the new smaller heat pumps like mini split systems.

Mini-split systems are a newer and advanced level of geothermal heat pumps which allow a homeowner to heat or cool only selected rooms. This selective approach is less expensive than a centralized system since most homeowners prefer conditioning only specific rooms.

Given the benefits of this combined system, many homeowners are preferring this system. But at the same time, if you are planning to install this hybrid energy system, you need to take a strategic approach. Here is what you need to do when opting for both solar and geothermal combined system. 

How Can Homeowners Use a Combined System?

If you are planning to own a renewable energy system, you should probably start with the geothermal system. We know solar is the most popular option but solar panel installation will be much effective if you plan to combine the systems. Many homeowners who choose to invest in a combined system start with a geothermal heat pump. In doing so, they can immediately reduce their heating and cooling costs while getting a feel for renewable energy. Once they have a little more history on their actual electrical usage, they purchase solar panels.

If you purchase solar panels before the geothermal installation, you may need to carry out some extra expenses. You will require far less energy with solar panel once you install the geothermal system. If you are planning to combine these systems, we advise you to install a geothermal pump first.

We know that these suggestions may become irrelevant if you already have a solar panel installation in place. The status of your roof is also crucial, we advise you to repair the rooftop before you move forward with the combined system.

Many homeowners are concerned with the one-time cost that comes with installing these two options in a combined system. The government has already accounted for the expenses of solar energy panels, adoption of geothermal will give you more tax benefits, making them more accessible.

In short, we advise you to carefully weigh all the options before you decide to combine these options. If you are careful about how you implement these changes, we are sure that you will end up making some excellent financial benefits and your transformation to these combined systems will be as smooth as possible. We just recommend you to explore in great detail before you dive into action. 

Step By Step Procedure to Incorporate Geothermal and Solar panel system correctly in your home 

1. Ensure a Tight Thermal Envelope: 

A home with a tight thermal envelope will ensure the highest efficiency for this system. The most important thing is to have the right type of insulation. Which is measured by the R-value. The R-value is the resistance offered by the insulation for thermal changes. Foam and cellulose insulation are the most popular ones maintaining zero air tolerance. There are different sealant options to prevent air leaks around your home. We suggest using spray foam, caulk, or weather stripping (depending on what structure you’re sealing) for windows, walls, fireplaces, etc. Making the home airtight and investing in the right insulation is the first step in creating the perfect environment for high efficiencies and optimum performance for home heating and cooling.

2. Install your geothermal system: 

If you insulate your home correctly with proper air sealers, the size of your geothermal pump will decrease considerably. Since geothermal pumps use solar energy to heat and cool, they require much less energy to operate, saving you money in the end and ultimately make your home free from electrical utilities. geothermal drops the peak electric demand in summer months by at least 30 per cent, allowing for more of the national base load to be generated by renewable energies. Installing a geothermal system before PV solar will lower the energy demand in your home, which reduces the number of panels needed or creates a bigger budget to help power other parts of your home.

3. Installing Solar energy panels:

Since you have an airtight home, with good insulation, you have dropped the energy demands required by your home and hence the size of your solar PV system will be much smaller. If by chance you end up making more energy then required, contact your local utility company about the net metering offer. When installing a solar panel system, you need to consider many options like the size of the solar system, the area your rooftop avails, where your solar panels will be located, is ground mounting an option (If roof space is limited), Where is the least shaded spot on your roof or ground that will give optimal direct sunlight? Being aware of these questions will help you achieve 100% solar coverage and no utility bills…saving money, rewarding renewable investments, and helping improve comfort in your home (or building).  

The Efficiency of a Combined System 

The best thing about this combined system is its efficiency. The geothermal pump will perform best in the months of October to December, while solar energy panels perform their peak during the March to June. These weird peak values complement each other perfectly to give you a efficient energy system, ensuring that consumers will benefit throughout the year from this combination. 

Benefits of a Combined Energy System 

This combination of two renewables will definitely offer great value to the amount of money spent. Whereas it will deliver superior performance compared to your traditional utilities. Here are some of the benefits of this combined system

  • Can provide full-scale heating even in the winter season
  • Provide air-conditioning during the summer season at a very low cost compared to the HVAC systems
  • Ensure flexibility in terms of how much heat is generated. Since the temperature of rocks remain the same irrespective of the surface weather condition and hence the geothermal’s pump output will not be affected.
  • In the summer, the ground source heat pump would discard the excess of heat produced by the solar collectors and store a part of it for the winter.

Conclusion

As you move forward with these suggestions, you will discover a lot of new things along the way. You can take full advantage of this system if you know what exactly you are doing. Review your options and if you already have a dealer don’t hesitate to  ask them any questions pertaining to the system.

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