Hydronic Heat Exchanger – Hydronic Heating Systems, Back From The Future?
A hydronic heat exchanger sounds fairly high tech doesn’t it? But in actuality water-based heat exchange structures or hydronic heat exchangers have been around since the 1800’s. These common boiler and radiator heating systems were very popular in the 1900’s, especially during the height of high-rise apartment building at the turn of the 20th century. But due to more efficient forms of gas and electric heating, hydronic heating systems fell into disuse in most modern residential construction. However this common form of central heating has had a resurgence based on concerns about heating and cooling costs and effects of on the environment. The purpose of this article is to provide an overview of hydronic heat exchangers and their place in modern home and building design.
What is a Hydronic Heat Exchanger Anyway?
A hydronic heat exchanger is basically a fairly simple system where water is used to either heat or cool a house or building. If you have ever visited a pre-1950’s building or house you may have seen a bulky old cast-iron radiator or two still around often hidden behind by screens or under a wooden cover.
With these older hydronic heating systems, water would be turned into stream by a gas or oil-fired boiler in the basement and then the hot steam would be sent to every radiator (the exchanger part in the hydronic heat exchanger) in the house.
These systems were often inefficient since the heat from radiators couldn’t be effectively controlled. This variable steam flow meant that the radiators closest to the boiler were frequently overheated while radiators further away had lukewarm heat or never got hot at all.
In multi-floor buildings, this meant the people on the first floors roasted while the ones on the other higher floors suffered from the cold. Not to mention that these old cast-iron systems if not properly installed allowed trapped air into the water supply which corroded the cast iron. This corrosion eventually lead to chronic water leaks, problems with pressure-relief valves popping open, annoyingly loud gurgling, banging and whistling sounds in the pipes and vents along with other maintenance headaches. But if done right, a cast-iron hydronic heat exchanger could last 30 years or longer.
Modern Hydronic Heat Exchangers
But now that has all changed with the development of stainless steel and copper tube based boilers and radiators. These new hydronic heat exchangers are designed to be much more energy-efficient. The stainless steel boilers use tubes filled with hot combustion gases to heat water into, which is then circulated to radiators that are designed to be slimmer with wall-mounts and safer water to air transfers.
The next type of design is the water tube. A water-filled system of tubes is heated by an electric, gas or oil-fired furnace and then the resultant steam is pushed to the radiant heat exchangers through-out the house.
A water-filled tube hydronic heat system has several advantages over a regular cast-iron or stainless steel boiler. First the tubes are made from copper. And since copper can conduct thermal energy more readily than either iron or steel, the water is heated up using less energy. Second the water tubes are often designed into a “fin” shape to increase the surface area and therefore increase the heating speed.
Now that you understand a bit more about the “tech” behind this venerable residential heating system, you can discover which hydronic heat exchanger structure best suits your needs and budget.
