水力平衡解决方案
Hydronic Balancing Solutions

Want to MakeYour Building Green? Pump less water in your HVAC System! Pumping less water in a hydronic system is the easiest way to save money on electric bills every month. While this may not earn you LEED points for a GREEN building design it does go a long way toward reducing the overall energy consumption of a commercial building. Unfortunately though, it takes more than just a design calculation to make this happen. When the system is being designed, the designer can make adjustments to the flow rate by changing the heat transfer selection criteria for coils and radiators. Out in the field though, the pump and the pipe find a "natural" flow rate regardless of the design calculation. The illustration shows how a typical pump and system curve react. Between design safety factors, and installation modifications, it's very easy for a system to operate with 15%-20% more water than expected. typical pump and system curve The actual flow rate is determined by the way the pipe and fittings are actually installed, and the pump's ability to deliver water. When too much water is flowing you spend more money - money to move the water, and money to heat or cool it. You can see that the example pump operates with an extra 1.5 HP. That difference in electricity adds up over time, and is never noticed. If the system gets the opposite though, too little water, occupant comfort is affected, and they'll find a way to become comfortable, which usually means opening valves for more water flow and as a result, more money to operate the system. Adjusting the water flow rate is called "balancing". Often, the pumps are larger than they need to be, and head and flow rates are over estimated. The end result is that system flow will be greater than design. Options to reduce this flow include limiting the pump discharge flow, or limiting the heat transfer devices' flow rates. To limit flow at the pump, a Bell & Gossett Triple Duty Valve is used to throttle the pump flow.

The extra advantage to the system is that the built-in check valve prevents reverse system flow, and depending on the type of Triple Duty Valve, it may also reduce the number of fittings required to install the pump. Plus, limiting the system flow saves pump energy. The other way to adjust the system flow is to balance the flow rates at the heat transfer terminals. Bell & Gossett Circuit Setter® Plus and Circuit Sentry™ balancing valves allow the water to be reduced to the optimal flow rate.