Circulation Is The Key To Comfort

May 1, 2003
by Jim Patterson The heating system is the heart of our home; and like our hearts, its operation determines how we exist. Can you imagine the repercussions

by Jim Patterson

The heating system is the heart of our home; and like our hearts, its operation determines how we exist. Can you imagine the repercussions if our heart operated like most heating systems?

What do you suppose would happen if blood flow were established only as each section of our bodies needed nourishment instead of providing a constant flow of essentials throughout our entire body as it does now? We would feel hot and cold because the temperature in our extremities would never stay constant. Maintaining a constant balance within our bodies would be difficult because of the varying flows, and the healthy tissue would suffer from the inconsistent pattern.

Do these symptoms sound familiar? I diagnose more unhealthy heating systems in a year than I thought possible. Many of the problems can be resolved by following the role model on which we all rely — our hearts.

It is the constant flow of blood that maintains a stable body temperature. Such a feat would be impossible without the blood’s constant circulation through our veins and arteries.

Now picture a hydronic heating system in place of your body. Pipes replace the blood vessels; the picture starts to evolve. Can you imagine the comfort we would enjoy if our homes maintained a stable temperature plateau like our bodies?

Fortunately, we have the prescription for the illness that makes many otherwise happy homes about as comfortable as a locker in the morgue. By allowing the boiler to circulate water through the radiators at a constant rate, we can eliminate the ups and downs we feel as our heating system cycles on and off trying to catch up to the heat loss. If we allow the system to keep up with the heat loss, the peaks and valleys will be erased, and a home’s cold will be cured.

The function that allows us to provide a hydronic heating system with the ability to keep up is referred to as weather-responsive control. By using an exterior sensor to provide feedback to the boiler, we can change the delivery temperature of the boiler to match the heat loss of the home. As the temperature outside changes, so does the temperature of the water within the hydronic heating system.

This constant monitoring of the environment allows us to keep up with the heat loss that occurs in a home. As the temperature gets colder outside, the heat loss of a home increases. The sensor tells the boiler to fire a little longer and raise the temperature a little. Keeping up provides the comfort and fuel efficiency that makes this type of control system unique.

Zoning Made Easy

In addition, by providing a constant flow, other design possibilities can be created. Non-electric valves can be used on individual radiators to provide zone control as needed. In this way, each radiator can become its own zone to provide even further comfort and economy of operation. We have designed many systems in which the owner has more than 20 zones of temperature control. The cost of using these valves is miniscule when compared with conventional installation and maintenance costs.

Radiant Heating

Radiant floor heating is another fantastic function of constant circulation. With formerly cold tile or hardwood floors warmed to a constant 85F, nothing beats the comfort we can provide with a little tubing under the floor.

We also can also extend the lifespan of the system’s components by changing the water temperature in which they work. Most applications can use 150F water or less to comfortably heat a home during 75% of the year. The reduction in thermal stress also will save your customers big bucks in repairs.

Versatile Hydronic Air Handlers Provide Cooling

Hydronic systems are often thought of as only providing warmth during the winter — it would be asking too much to allow for air conditioning on those hot, humid summer days. Not so.

Consider a hydronic air handler system. It can provide greater versatility, efficiency, and total comfort for your customer. How does it work? The air handler consists of a multi- or variable-speed blower, hydronic heating coil, and an air conditioning coil inside a single cabinet. The air conditioning coil is connected to an outside condensing unit.

During heating mode, the hydronic heating coil is connected to the boiler. When there’s a call for heat, the thermostat activates a small pump and transfers hot water from the boiler to the hydronic coil. There, the water circulates through the coil. The blower pulls (draw-through style) return air from the building and forces it over the hot hydronic coil. Warm air is then distributed through a duct system, as the cooled water from the heating coil is recirculated back to the boiler for reheating.

In the cooling mode, refrigerant is circulated from the outdoor condensing unit through the cooling coil located in the air handler. The same duct work is used to distribute air conditioning comfort to the building.

The versatility of a hydronic air handler system comes from using a gas or oil boiler to provide heat, while still allowing for air conditioning in the summer. Besides ducted heat and cooling, a boiler can be used for radiant floor heating, domestic water heating, and snow melting.

Editor’s Note: Contact your hydronic manufacturer or distributor to find out more about hydronic air handler options available with products you may already be using for heating-only applications.

Jim Patterson is senior vice president of Orchard Valley Technology, a contracting firm in Haydenville, Mass. He can be reached at 413-268-8381 or [email protected].