Distribution pump arrangement for a hydraulic distribution system having changing flowing direction

A distribution pump arrangement for a bi-directional hydraulic distribution grid configured to distribute thermal energy, the bi-directional hydraulic distribution grid comprising a hot conduit configured to bi-directionally allow heat transfer liquid of a first temperature to flow therethrough and a cold conduit configured to bi-directionally allow heat transfer liquid of a second temperature to flow therethrough, wherein the second temperature is lower than the first temperature, the distribution pump arrangement comprising:

• a hot conduit control valve in the hot conduit;
• a first distribution pump having an inlet connected to the hot conduit at a first side of the hot conduit control valve, and an outlet connected to the hot conduit at a second side, opposite the first side, of the hot conduit control valve;
• a pressure difference determining device arranged beyond the second side of the hot conduit control valve and configured to determine a local pressure difference, Δp, between a local pressure, phot, of heat transfer liquid in the hot conduit and a local pressure, pcold, of heat transfer liquid in the cold conduit, wherein Δp=|pcold−phot|;
• and
• a controller configured to:
• while Δp<a threshold value, set the distribution pump arrangement in a flowing mode, wherein:
• the first distribution pump is set to be inactive, and
• the hot conduit control valve is set to be open, thereby allow a flow of heat transfer liquid of the hot conduit through the hot conduit control valve;
• while Δp≥the threshold value and pcold>phot, set the distribution pump arrangement in a hot conduit pumping mode, wherein:
• the hot conduit control valve is set to be closed, thereby stop a flow of heat transfer liquid of the hot conduit through the hot conduit control valve, and
• the first distribution pump is set to be active, thereby reduce the local pressure difference.