Air Management For Hydronic Heating and Cooling Systems A-307A
Bell & Gossett A Complete Line of Air Elimination Products for Commercial Heating and Cooling Applications C Pressure Reducing Valve Every heating, cooling or dual hydronic system requires effective air management to provide maximum performance efficiency. Proper air control enhances hydronic system energy efficiency by helping reduce Rolairtrol Air Separator pipe corrosion and scaling which adds extra unnecessary friction losses.
B Rolairtrol® Air Separators For Hot and Chilled Water Systems • Remove entrained air to protect system against damage. • Eliminate noise caused by air bubbles. • Tangential flow pattern increases efficiency. • Chilled water buffer tank capability. C High Capacity Air Vent Model 107A • Float-actuated operation for the instant venting of free air. • Rugged cast iron construction with stainless steel, brass and EPDM internal components. • Positive shut-off at pressures up to 150 psig.
Supreme Air Separation for Commercial Systems Its tangential design creates a whirlpool inside the vessel, sending denser air-free water to the outer section near the shell, while the separated air migrates to the low-velocity center where it is drawn to the air collector. The separated air is removed from the system through the Hi-Capacity Air Vent in an air elimination system, or directed to the compression tank in an air control system.
Rolairtrol Features Rolairtrol Benefits A Tangential Flow-Through Design Patented B&G Design – The Rolairtrol provides maximum air separation efficiency due to a combination of centrifugal force and velocity reduction. The Rolairtrol’s tangential design creates a whirlpool inside the vessel. The tangential design had the greatest air separation efficiency when compared to less effective, straight flow separators or coalescing designs.
Air Separation Efficiency Comparison 100 First Pass % of Air Removal 90 80 B&G 70 Competitor-A 60 Competitor-T 50 Competitor-W 40 Competitor-S 30 Typical flow through 6” pipe 20 10 0 0 200 400 600 Flow in GPM 800 1000 1200 (All performances as tested by B&G) Rolairtrol vs.
The air in a closed hydronic system is managed by using one of two techniques. In the Air Control method, the air cushion and system water actually touch. During the fill and system pressurization step, all excess air is vented and the required air is stored in a compression tank where it acts as a cushion for the expansion and contraction of the system water volume. Changes in the system temperature and pressure change the solubility of air in water.
How the Rolairtrol Works In order to evaluate air management of a specific application a better understanding of how temperature and pressure affect the solubility of air in water is required. Air is a mixture of gases, approximately 80% nitrogen, 20% oxygen and trace amounts of others. Within a short time after the initial fill, the air in a properly operating closed system begins to lose its oxygen content through oxidation.
Velocity Gradient of Water in a Rolairtrol The picture to the right illustrates the velocity change for water passing through an RL Rolairtrol. A computational fluid dynamics program, using color to depict the changes of fluid velocity and flow path within the Rolairtrol vessel, was used to create this illustration. The green color indicates the higher velocity fluid; the dark blue a low velocity fluid.
Compression Tank & Airtrol Fittings Pre-charge tanks are designed to absorb the forces of thermal expansion in hydronic heating and cooling systems. The rubber membrane completely isolates the air from the system fluid, which prevents waterlogging of the tank. The pre-charge minimizes the size of the tank.
H F Inlet G H F To Compression Tank D B H To Compression Tank Inlet G H A Date Plate D BA Outlet Approx.
Trust the name that set the standard in the HVAC industry – Bell & Gossett. For over 90 years Bell & Gossett has brought you the most reliable and innovative products for hydronic, HVAC and plumbing systems. From pumps and heat exchangers, to air management systems and valves, Bell & Gossett knows what you need to get the job done right the first time and provide lasting value. Your local Bell & Gossett representative is an experienced professional with a wealth of technical expertise.
