Geothermal and Thermal Storage Ventilation
Tackling Today’s Building Challenges with Integrated Heating and Cooling Solutions
The construction industry today is at a crossroads. Global warming has made building efficiency and carbon reduction an imperative across the globe. But the recent pandemic has also elevated ventilation safety as an important construction consideration from this point forward. Addressing these two issues can often mean sacrificing one goal for the other – in addition to adding cost and complexity to the overall building design.
Electrification of Buildings
To tackle the issues of building efficiency and decarbonization, many regional initiatives have moved toward building electrification.
Electrification of homes and businesses has been deemed an important component of plans to reach today’s greenhouse gas reduction goals. According to Edison International, in places where there is strong renewable energy uptake, electrification can reduce GHG emissions in homes by up to 60 percent in 2020 and by up to 90 percent in 2050 (compared to homes that use both gas and electricity). This is the only approach to home decarbonization that has been demonstrated to have results that are this significant.
There are, however, some unintended consequences of electrification. One pressing issue for utilities will be the fact that there will be less of a night-time drop in electricity consumption compared to today’s generation profiles. Generally, there is less electricity demand at night when people are sleeping. With electrification, in both summer and winter, electricity demand will remain somewhat strong throughout the nighttime hours to meet demand for electrified heating and cooling. Storing enough renewable energy (using batteries) for use throughout the night demand period would be hard to accomplish and also very expensive.
It’s a Thermal Storage Problem, Not an Electricity Storage Problem.
Using available technologies and engineering techniques to store and use thermal energy provides several strong solutions to the problem of expensive and complex electricity storage. These solutions include Geothermal Heat Pumps and Integrated Ventilation Design which provides active thermal storage and management within a building.
Geothermal Heat Pumps
Although many parts of the country experience seasonal temperature extremes — from scorching heat in the summer to sub-zero cold in the winter—a few feet below the earth’s surface the ground remains at a relatively constant temperature. The earth is generally more resistant to seasonal temperature changes than air. Consequently, the ground only a couple of meters below the surface can act as a very efficient heat sink/source with a geothermal heat pump.
In the summer, a geothermal system collects heat from your home and moves it to the much cooler earth. During the winter, it draws from the much warmer underground temperature providing an efficient means to heat a home or building, including in some instances covering its water heating needs as well. While electricity is used for the operation of a geothermal system it utilizes from 25% to 50% less energy than your conventional heating and cooling systems, reducing emissions and energy consumption by approximately 44% overall.
Thermal Integrated Ventilation Solutions
In addition to Geothermal Heat Pumps, there is an inexpensive and effective solution that can tackle both efficiency and ventilation safety while actually reducing construction costs for a typical building.
Integrated ventilation is a hybrid concrete and HVAC smart floor system that reduces building energy consumption while providing exceptional ventilation safety. Integrated Ventilation feeds air through ducts created in the hollow core (or cast in place) concrete floors to take immediate and full advantage of the thermal properties of concrete.
Integrated ventilation design combines four systems into one: heating, cooling, fresh air ventilation, and thermal energy storage. When the concrete structure of a building is paired with the heating and cooling system of a building, energy consumption reductions of 40%+ can be achieved with no moving parts, no new equipment, and no complex software applications. Conditioning the temperature of the concrete floors with outside air at strategic times during the day and night using simple fan motors allows this system to maintain comfort levels in the building without utilizing the heating or cooling elements of the HVAC system itself. This is extremely energy efficient and illustrates the thermal power of concrete when used as part of the ventilation system.
Most of the year, integrated ventilation operates as a dedicated outdoor air system (DOAS) – bringing fresh air indoors, while maintaining the highest standards of air quality and occupant comfort. Recirculation of stale air is rarely necessary, preventing sick building syndrome and the potential spread of infectious diseases such as the recent COVID pandemic. Year-round, non-hydronic radiant comfort provides the best occupant experience.
Integrated ventilation is enabled by this simple L-shaped duct (picture to the right) that connects the flooring system with the HVAC system. There are no moving parts, and no new pieces of equipment to install. In fact, buildings with integrated ventilation look largely the same as any standard building, except for the fact that many of the mechanical systems, including the HVAC system, can be reduced in size or eliminated. Integrated ventilation costs from $10 – $50 per square foot less than standard buildings of the same design, mainly due to these reductions and eliminations.
Conclusion:
Energy efficiency and ventilation safety have become high priorities for many stakeholders in the building industry. These can be, but don’t have to be, mutually exclusive goals.
Utilizing the building structure as part of the ventilation system of a building helps to increase energy efficiency and ventilation safety, while also reducing upfront and ongoing costs. Combining thermal ventilation solutions with geothermal heat pump systems can add even more efficiency while enhancing the return on investment for the building and internal building systems.
Heating and cooling solutions that use thermal energy scavenging or recovery provide a strong inertia against temperature fluctuations. This helps to stabilize internal building temperatures in winter or summer and provides a largely self-regulating indoor environment. In extreme weather conditions this adds resilience and safety to the building and its occupants – another beneficial trait.
Electrification will help solve some of the building stock’s most pressing sustainability issues. Geothermal combined with integrated thermal ventilation solutions enhance building efficiency, safety, and resilience while also enabling a more renewable and stable grid.
