Taking the pressure off

Hydronic balancing is one of the most complicated tasks faced by heating engineers, and a poorly balanced system means a system, which is both energy inefficient and costing money.

To help take the pressure off engineers, Albion recommends specifying intelligent valves to help strike the perfect system balance. Dynamic valves such as Pressure Independent Control Valves (PICVs) and Differential Pressure Control Valves (DPCVs) are like pneumatic mechanisms, but instead of using oil or air they are operated by water pressure.

Their intelligence comes from their  ability to adjust as the system changes, allowing them to read the conditions, attune accordingly and help prevent the system over delivering and wasting energy.

PICVs promote balance and control, they are generally installed at end of line energy sources such as air handlingunits, fan coil units and chilled beams, which offer the best position from which to regulate performance of the heating system.

By constantly self-regulating to system variances, PICVs ensure pressure influences from the rest of the circuit are avoided, promoting excellent control of the flow requiredto each unit in accordance with the demand for either heating or cooling.

Additionally, PICVs save time and cost, from a designer’s perspective they require less complicated calculations, from an installer’s  perspective there are fewer valves to install giving both space and financial savings. For a commissioning engineer they give flow verification but with no balancing work required so delivering a better performing system all  round.

The other smart valve in the intelligent valve mix is the DPCV. This differs from the PICV in that the differential pressure is controlled at the precise location it is installed  in, therefore  allowing  the flexibility of phased commissioning or balancing  of each sub-circuit.

DPCVs offer beneficial energy savings in ‘real life’ installations through eliminating localised overflows in sub-circuits that  often occur within poorly balanced and controlled  radiator applications.

In a variable volume system when the heating or water flow is not needed in  a building, a DPCV has the ability to prevent it from circulating using its integral intelligence to conserve the energy that would be otherwise wasted. So common inefficiencies, such as water losing energy to its surroundings, heating losing heat or cooling gaining heat into the pipe distribution system need not occur.

Dynamic valves ensure performance and comfort so there is no human interaction required to counter the badly balanced system . With the introduction of dynamic balancing products onto the market there is an increasing opportunity to simplify the entire process of balancing a system for heating engineers, as well as cutting costs and improving consistency. The choice of equipment is key to achieving  a well-balanced system.

The specification of equipment for a building system can help enable systems to ’empathi se’ and compensate for any inefficiencies that occur in other systems that may negatively impact in the overall running of a building. For example in a central heating system. mixing valves provide the ability to regulate the temperature of the heating pipes in a climate by controlling the flow of hot water from the central supply system to the local heating zone.

By carefully adjusting the temperature of the water in the heating pipes, the  heating controller is able to closely balance the energy applied with the heat loss, which results in optimum balanced room temperature management.

The controller constantly monitors both the room and outdoor conditions and compares them to target values. It then calculates the desired pipe temperature required to sustain the current air target  set point and positions the mixing valve to achieve this pipe temperature.

Temperature sensors are used to provide feedback correction for valve positioning. This function is known as ‘weather compensation’ and when done correctly allows the boiler to modulate its performance and deliver much lower temperatures into the system. Such adjustments would most likely occur on mild spring or autumn days when not so much heating is required and it is not necessary to create a high temperature.

Intelligent management systems not only inform engineers and help create better performing buildings and industrial systems they can also compensate for human error. For example a typical example of an energy saving being made could be if a factories heating or cooling system was operational and a window had been left open, there is the option to isolate and shut off the heating in a specific part of the system to help prevent energy wastage. Some systems do this by reading a rapid drop in temperature in a particular zone, so they close off automatically using a 2 port motorised control valve (MCV) only re-open­ ing when room temperature  stabilises. Or, if a building is unoccupied at night, the 2-ports MCV prevents circulation of water flow in closed circuits and also open circuits such as WCs and basins so reducing the risk of water wastage, leaks and energy loss.

Additionally, in a hot water system a common application driven by an intelli­gent management system is when a 3-port MCV is in place to divert hot water to the system cylinder when it needs topping up even though heating demand may still be on and calling for heat.

Whilst the heating may be off for a short time, when the hot water cylinder heats up it ensures thereis hot water delivery at all times, the function is simple but effective. The flow is sent to the cylinder first when required and once satisfied flow is then resumed through the heating circuit.

Also, with the increasing specification of renewables such as biomass or solar, the 3 port MCV is often used for its diverting function to ensure the renewable energy source is used as priority until its capacity is exhausted.