Heat Pump Control: Variety without Limits

Waterkotte has reacted to market requirements with enhanced software
The software for the enhanced Waterkotte controller already takes into account all the requirements posed of a heat pump heating system. Effective immediately, all of this heat pump manufacturer’s models are equipped with this programming as standard. According to the company’s own statements, this development prevents communication errors between individual system components and simplifies the cabling of complex systems. Waterkotte, which recently received an infusion of a considerable sum of capital for the future, regards itself as a market leader.

The difficulties in practice
Today, reality looks like this: “If, for example, a solar system and three mixing circuits, possibly also a pool should be combined with the heat pump, this is hardly possible from a single source. The boxes for activating the mixers and the pool are generally supplied by third parties. Again and again, this creates significant communication difficulties. The box does not understand the controller correctly or the mixer does not understand the box. For example, the actuators must be able to detect using the activated logic whether the system is heating or cooling. Frequently this data exchange only works with additional signal couplers and electronics. Freeing such data lines from all stumbling blocks assumes an advanced state of knowledge.”

Therefore, today Waterkotte is making available one piece of software for nearly all cases, and in addition, the electronic modules as communication interface with the actuators. Claus Fischer: “By default, our controller already allows the processing of a multitude of analog and digital inputs. Of course the requirements for a particular project can also exceed the normal scope. Then additional data exchange modules can be added without a problem. These boxes sit in a switch cabinet on top-hat rails. They are simply plugged in, without any assembly, and the wires are connected. The installation is ready for use right away since the software is prepared for the processing of the signals.”

Complete circuit diagrams for nearly all cases
Planners and installers no longer have to think long and hard about the components required for complex systems. An extensive library with approximately 600 standard schemes for the various heat pump series and the widest variety of combinations with heat generators, heat consumers, circuits, temperatures, etc. simplifies the planning and makes installation easier. The Waterkotte controller specialist: “If in a project a variant other than these 600 samples must be implemented, our back office is happy to advise. They will formulate the appropriate scheme. However our catalog already covers most cases, even concrete core activation or floor heating combined with room air technology.”

And the support continues all the way to the finished switch cabinet. “For projects with several machines, in the first step we deliver just the controller technology if this is what the customer wants. If he then determines that procuring the peripheral devices, that is, the various boxes and the switch cabinet, could be too complicated, he can also get the entire switch cabinet from us. He does not have to configure the architecture himself if he does not want to; alternatively he can have what he needs assembled by an electrician. We supply either both the controller hardware and the software or an all-in-one, worry-free package in the form of a completely-assembled switch cabinet.”

All-in-one, worry-free package on request
Then only the sources and consumer have to be cabled, whether they are circulation pumps, signal lines or various sensors in the field. “However the scheme from our program library specifies precisely where in the system which sensor and which drives go. Everything is marked exactly so that you can find it in the switch cabinet right away and connect it.”

Planners and installers are often overwhelmed by the custom-tailoring of circuitry. “We had to recognise this and react to it. Accordingly, we have standardised many solutions and enhanced our software for this. For example, we have a few heat pump types,” explains Andreas Jung, the Technical Managing Director, “which are not equipped with internal pumps. Here it is possible to activate external units regularly. Of course the integrated software allows this today by default. Furthermore, we have optimised process water heating by programming new switch-off criteria that charge the tank better. As in the past, we can not only control the heating systems via the return temperature; instead, according to the requirements of the project in question, we can even control the temperature in external tanks and of course this depending on the outdoor temperature.”

The advantage is this: “If, for example, a solar system or another heat generator such as the wood carriers of a wood-burning stove is connected to such a tank, and these are only active depending on the time of year, this switch prevents excessive temperatures from traveling in the direction of the heat pump.”

A few years’ development work
When it comes to such controller and software offerings, Waterkotte has taken a big step forward with this solution. This took several years of work. A heating configuration with renewable energies can only play out its efficiency if the system has been optimised. Much technical building equipment throws away efficiency because the individual products are not attuned to one another, and due to this insufficient compatibility, the devices can only communicate with one another via detours.

“Experience shows that in many cases a bid is put out for the hydraulic system of a heat pump system without describing the exact functions of the associated control system. When it comes to the installation, the system builders have to consider carefully how they will accomplish making the components receive and process the various signals correctly. This is simply the disadvantage when third-party products have to be incorporated. We have experienced it in our own company that customers call and complain that X does not communicate properly with Y. So we have learned from this. Developing and supplying a total control-technical solution is the only right and feasible way to accommodate the increasing complexity of heating systems.”

Two qualifications under one roof
This does not mean that Waterkotte also wants to establish itself as a controller company in the future. “Our offerings relate only to our heat pump systems. We hope that with these we have achieved a market advantage that will meet with acclaim from system builders, planners and architects. They are the first ones confronted with repeated operational faults. What can we do better than anyone else? The big controller companies develop great hardware, but frequently they are lacking the process expertise for heat pump systems. At our company, we possess both qualifications. We have the process expertise, we rely on controller hardware that is established on the market, and we provide all of the programming from a single source.”

What details do the planners at Waterkotte need in a particular case? “Actually, we need only the requirements for the project: the heat output and the temperature level, the functions heating, cooling, passive, active, which consumers and which heat sources should be connected. Our program library then provides us with the appropriate hydraulic structure. And we then assign the appropriate dimensions of the peripheral devices to this structure: the size of the tanks, the output of the circulation pumps, etc. This way you end up with a completely bid-ready system.”

More information at www.waterkotte.de

• CID: 20140