SOURCES INTRODUCTION

REG System allows one or more Energy Source to be activated when the system requires it.

For example, sources can be:

1. Boilers

2. Heat Pumps

3. Thermo fireplaces

4. Biomass boilers

5. Pellet Stoves

Besides these “simple” sources that are controlled by digital contacts (start/stop, summer/winter, first/second stage), the system allows the management of one or more generators with the Opentherm protocol, which is a sort of special fourth source (HEATING/COOLING OPENTHERM and DHW OPENTHERM); furthermore, by using dedicated interface modules, it is also possible to control sources via various types of protocols (e.g., heat pumps managed via ModBus protocol, see REG-UGW-485 manual).

Sources managements is closely linked to the managements of the Circuits/Manifolds, as they activate the sources in the first instance; for each Circuit/Manifold, it is necessary to specify which sources to activate in summer and which in winter (SOURCES SETTING IN THE CIRCUIT PAGE)

For example, suppose you have a system with 2 circuits:

• Circuit 1 is for high temperature and serves towel radiant heaters, in winter only, from a gas boiler

• Circuit 2 is for low temperature and powers a radiant floor, both in summer and winter; it is powered by a heat pump both in summer and winter; if the outside temperature drops below 5° in winter, the gas boiler is also activated.

To control the system, we can consider the boiler as Source 1 and the heat pump as Source 2; at this point we will set the circuits in this way:

• Circuit 1 (high temperature) is associated with Source 1 (boiler) in winter, with no source in summer.

• Circuit 2 (low temperature) is associated with Source 2 (heat pump) in summer; with Sources 1 (boiler) and 2 (heat pump) in winter (we will see later how to operate the heat pump instead of the boiler depending on the outside temperature).

The Source management is therefore divided into three phases:

1. Active Circuits determine which source or sources can be activated.

2. The logic of Source management makes further checks (on outside temperature, possible alarms, priorities, etc.) and determines which of the sources that can be activated (defined by the circuits in the previous phase) are actually activated.

3. A check is made on the temperature of the sources that are actually active in order to control or monitor it. This last step is not always required, it depends on how the system is designed.

This architecture allows, as will be seen, many practical cases to be handled:

• Different circuits activate different sources:

  • Some circuits activate a boiler, others activate a second boiler.

• The same circuit activates a source in Winter (e.g., Boiler) and another in summer refrigeration unit)

• The system activates a heat pump in summer; in winter the same heat pump is activated as long as the outdoor temperatures make it efficient; when the temperature drops below a certain value, a boiler is activated.

Some types of sources also allow you to specify the required water outlet temperature, for example:

• Boiler connected via Opentherm

• Heat Pumps connected via ModBus

• “Simple” sources via 0/10 V

In this case, the system sends the source the required temperature calculated by the circuits that require the source to be switched on. If several circuits are switched on at the same time, the source required temperature is either the highest in winter mode or the lowest in summer mode. Each circuit allows an offset to be specified between the temperature calculated by the circuit and the required source temperature.

The offset makes it possible to compensate the presence of heat exchanger, buffer tanks, etc. which may introduce temperature losses between the source and the user.

The offset between circuit temperature and source temperature can be set independently between summer and winter.

For example, if a circuit is calculating a climatic demand of 35°C and a source offset of 8° is set, a water outlet temperature of 43° (35+8) will be demanded to the source.

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