John Seigenthaler: Renewable Heating Design

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Like most people, I have opinions and beliefs about our current energy sources, and specifically how they play into the future of hydronic heating and cooling technology.

System COP is a more relevant metric of geothermal heat pump performance since the owner is paying for the electrical energy to operate the heat pump and the circulator, and their operation is always simultaneous.

The goal is to keep the system COP as high a possible as the operating conditions of the heat pump change. The logic behind maximum COP tracking is to continually look for an earth loop flow rate that improves the system COP.

Every year, manufacturers develop new or improved products for the North American hydronic market. Product development planning by those manufacturers depends on several factors. Here are a few of the main considerations.

Multiple boiler systems have been used for decades. They allow full heating capacity to be delivered when necessary, while also retaining high efficiency under partial load conditions compared to a single large boiler.

When a fixed output heat pump supplies a highly zoned heating or cooling distribution system, a buffer tank is typically used to prevent the heat pump from short-cycling under very low load conditions.   

ades of dealing with hydronic systems, I’ve confirmed two characteristics that always govern their operation. Both are rooted in the tenants of thermodynamics. Neither should be thought of as mysterious. 

Those who evaluate the performance of HVAC source equipment such as boilers, furnaces and heat pumps have to work with a wide variety of acronyms. Some of them were spawned by government bureaucrats, mostly the U.S. Department of Energy (DOE). Others were created through a consensus process based on input from manufacturers and other industry stakeholders.

Over the years I’ve had opportunities to work with several architects. They’re interesting people who have the ability to meld art with building technology. Sometimes the result is more “art,” and sometimes it’s more “building.” In either case, their designs typically get handed off to engineers with the simple request: Figure out how to heat my creation…

Given the current upward trend and volatility of fossil fuel pricing, there’s renewed interest in heating using wood pellets. Federal incentives that currently cover 26% of some qualified equipment adds enticement toward purchasing pellet-burning stoves.