6 May 2010
For many years the Danish pump manufacturer, Grundfos, had the same problem as Frese: they both had excellent products that generated substantial energy savings in cooling and heating systems, but it was difficult to quantify those savings.
At a strategy seminar in the summer of 2008 the two parties discussed their mutual problem. How can you verify the energy savings obtained with Grundfos variable speed pumps and Frese dynamic valves installed?
Suddenly, the solution appeared from the discussions: we needed to simulate a basic system using both products to calculate and verify the data. "We realised that if we worked together we would be able to tell how much energy can be saved in the system," said Stephen Hart, Sales Director, Frese A/S.
The setup of a combined cooling system based on dynamic valves in, for example, a hotel is quite simple compared to a traditional system based on constant flow or pumps running at constant speed.
When the dynamic valves used in connection with a variable speed pump for a hotel cooling system are installed, it is also necessary to install sensors at the end of the system to measure the available pump head. The interaction between the pump and the valve is optimal when the pump sensors are at the far end of the system.
Although more efficient, this system is much simpler than a traditional cooling system. When installed it only takes a few hours to commission a combined cooling system, compared to the weeks it normally takes to adjust a traditional system.
While the systems regarded as representing best practice today can save up to 50 percent of the energy consumption compared to a system fitted with a constant speed pump - which is already a good saving - the combined cooling system based on a Grundfos variable speed pump and Frese's dynamic valves can save an additional 26 percent of the pump energy cost.
This means that if Grundfos' variable pumps were used in combination with Frese's Optima Valves in all current installations, every 11th coal-fired power plant in the world could be closed. The total saving would be 9.5 percent of global energy production from such power stations.
"The dynamic valves and variable speed pumps in the variable flow system are able to adjust the pump power consumption on the basis of the changes in temperature in a room during the day. This is not the case with traditional systems. To use an analogy with a car - in a traditional system based on constant flow or pumps running at constant speed, you have the accelerator hard down permanently and you adjust the speed by pressing on the brake. With our system, there is no need for a pump to work harder than it needs to," explained Jens Johansen, Product and Marketing Manager, Frese A/S.
After the findings at the strategic seminar held at Frese's head office in Slagelse, Denmark, the necessary data were simulated and verified. In the spring of 2009 the variable flow system and the data regarding energy savings were presented at an international conference in London for engineers in the building trade.
"We took the right decision at our strategy seminar in 2008 when we decided to move on from being a company focusing mainly on commissioning technology to being a company focusing on energy savings and proven results. The recent positive international response to our case study and the resulting data give us high hopes for the future development and sales of our variable flow systems in collaboration with Grundfos," said Stephen Hart.
"Grundfos is dedicated to sustainable development through innovative products and systems. In combination with automatic balancing valves, speed regulated pumps like our Alpha 2 and Magna give full value for money and system efficiency. In this respect our cooperation with Frese is very promising," said Peter Reynolds, Managing Director, Grundfos Pumps Ltd.
Total savings:
Savings per coil using an OPTIMA solution:
The new Frese Optima combination valve is designed to combine automatic balancing and full modulating control regardless of the pre-set flow. The Frese Optima is an intelligent control valve that adjusts itself automatically to the changing pressures in the system while still being able to provide full stroke-modulating control. When the installer pre-sets the valve according to the maximum design flow the stroke of the control valve remains the same, thus providing 100% modulating control. In practical terms, the Optima ensures that there are no overflows and that below the design flow the valve has total authority.
