Energy storage takes many forms and is increasingly being utilized in a variety of settings, thanks to the growing utilization of renewable energy technology. The need for energy storage results from the fact that most forms of renewable energy production are intermittent, while our demand for energy is not. When designing and building systems which require energy storage, it is important to consider multiple factors to ensure the type of storage selected is best suited for the need.
Let’s consider water heating. In an emission-free setting, there are two primary choices available for heating water – resistive electric and heat pumps. If one deploys an instantaneous water heating system, or a system with minimal storage and quick-recovery capabilities, the intermittent demand will require a high-amperage, short-duration solution. This spells trouble for the broader electric transmission and delivery systems. Most of us, especially in densely populated regions, tend to perform household activities at roughly the same times. If too many of these high-demand systems exist in close proximity to one another, the need for massive power delivery systems becomes untenable.
Coping with demand peaks means we need to look at energy storage to spread the load out. For thermal applications, where the end use is taking advantage of thermal energy (heating or cooling), thermal storage is the go-to, most-cost effective solution. Time is the arch-enemy of thermal storage. The effects of heat-loss on the overall efficiency of a system diminish when loads are characteristically more frequent and consistent. Among all of the loads in a structure in which humans inhabit, domestic water heating is the most predictable and consistent with demand peaks occurring twice per day.
The benefit of thermal storage in a domestic water heating system is clearly visible as it allows for a smaller heat source to satisfy any given load over a longer period of time and the impacts of heat loss are minimal. If we look beyond the single structure, there are additional layers of benefit which are unique to domestic water heating systems which utilize heat pumps. The heating capacity of an air source heat pump is higher when ambient temperatures are warmer, and lower when the outdoor temperatures fall. Heat pump systems are typically designed to meet the maximum demand potential for hot water on the coldest day of the year, resulting in generous over-capacity in all conditions except the coldest day of the year. This over-capacity can be aggregated by the NWHS e-cloud to provide beneficial load management, load shedding, advance load-up and other regulation services.
Heat pumps represent the only emission-free path to heating water with an efficiency greater than 100%. They also rely on storage to operate efficiently and thus, can provide the benefit of energy storage and demand response to the broader net-zero community. Learn more about our products and technologies at water.nyle.com;