Introduction of Hydronic Systems
This post's objectives are as follows:
2. Describe the primary advantages of hydronic systems.
3. Discuss some of the difficulties associated with hydronic systems.
4. Describe how a water-source heat pump system works and what it can do for you.
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In this post, we'll look at systems where water-heated and/or water-cooled equipment provides the majority of the heating and/or cooling.
In some buildings, these systems will heat with low-pressure steam rather than hot water. We will assume that hot water is used as the heating medium for the rest of this chapter.
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Hydronic systems are most commonly used where high and variable sensible heating and/or cooling loads occur due to their ability to produce high output on a ‘as-needed basis.' Perimeter zones are typically used in this situation.
Advantages of hydronic systems:
1. Noise abatement
2. Economical, as a result of low operational costs
3. Economical due to low initial costs
4. Energy conservation
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Disadvantages of hydronic systems:
1. Ventilation
2. Failure of the system
3. The level of humidity
Heating Systems Using Natural Convection and Low-Temperature Radiation
The most basic water heating systems are made up of pipes that have hot water flowing through them. Because the output of a bare pipe is generally insufficient to be effective, an extended surface is used to dissipate more heat. There is a diverse range of heat emitters.
Changing the Flow of Water
Throttling the water flow allows for local zone control. The simplest method is to use a self-contained control valve mounted on the pipe. This valve contains a capsule of material that changes volume dramatically depending on room temperature. As the temperature rises, the material expands, closing the valve.
A wall thermostat and water control valve is a better, but more expensive, method of control.
When the load is high and the flow is high, controlling the water flow by modulating, or adjusting, the flow works best.
Changing the Temperature of the Water
The heat loss through a wall or window is proportional to the temperature difference between the two walls. As a result, a control system can be set up to raise the water temperature as the outside temperature drops, causing the heat output from the water to rise in lockstep with the increase in heating load. Outdoor reset is the name given to this type of control system.
Complying with Ventilation Requirements
1. Open Windows: Water systems are frequently used in conjunction with occupant-controlled windows (opening windows).
2. Window air conditioners: Heating and window air conditioners are a step up from heating and opening windows.
3. Separate ventilation systems with optional cooling: Another option is to install a separate system for ventilation and, if necessary, cooling. In cooler climates, this is a very common design.
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