Method and arrangement for optimizing heat transfer properties in heat exchange ventilation systems

A heat exchange system (200) of a ventilation system configured to deliver heat to incoming air by outgoing air heating a heat transfer fluid, for the heat transfer fluid to transfer the heat to warm incoming air, a level of an antifreeze agent in the heat transfer fluid being dependent on a temperature of the incoming air, the system comprising:

• a heat collector unit (225) configured to collect the heat from the outgoing air;
• a heat deliver unit (230) configured to deliver the heat collected from the outgoing air to the incoming air, the heat collector unit and the heat deliver unit in fluid communication with each other;
• a separator (250) adapted to separate and remove an amount of the antifreeze agent from the heat transfer fluid;
• a remixer (245) adapted to add a part of the antifreeze agent to the heat transfer fluid;
• a first temperature sensor (275) configured to monitor the temperature of the incoming air, the first temperature sensor located upstream of the heat delivery unit (230);
• a second temperature sensor (280) configured to monitor a temperature of the heat transfer fluid;
• and
• a control unit (285) operatively connected with the separator (250), the remixer (245), and the first and second temperature sensors (275, 280),
• the control unit adapted to analyse current temperature data provided by the first and second temperature sensors (275) and to selectively order i) the separator to remove the amount of the antifreeze agent from the heat transfer fluid, and ii) the remixer to add the part of the antifreeze agent to the heat transfer fluid, based on the analysis of the current temperature data,
• wherein the heat collector unit i) delivers heat to incoming air by outgoing air heating the heat transfer fluid, and ii) transfers the heat from the heat transfer fluid to transfer to warm incoming air,
• wherein the control unit, in the analysis of the current temperature data, is adapted to further analyse long-term statistics over relations between the monitored incoming air temperature, previously chosen levels of the antifreeze agent associated with the monitored temperature of the incoming air, and a resulting temperature of the heat transfer fluid for a local installation, the long-term statistics being based on actual monitored incoming air temperature values and the monitored resulting temperature of the heat transfer fluid for the local installation in the operation of the heat exchange system of the ventilation system.

A heat exchange system (200) of a ventilation system configured to deliver heat to incoming air by outgoing air heating a heat transfer fluid, for the heat transfer fluid to transfer the heat received from the outgoing air to warm incoming air, a level of an antifreeze agent in the heat transfer fluid being regulated dependent on a temperature of the incoming air, the system comprising:

• a heat collector unit (225) located with an outgoing air duct and configured to collect the heat from the outgoing air;
• a heat deliver unit (230) located in an incoming air duct and configured to deliver the heat collected from the outgoing air to the incoming air, the heat collector unit and the heat deliver unit in fluid communication with each other;
• a separator (250) connected to the heat deliver unit and adapted to separate and remove an amount of the antifreeze agent from the heat transfer fluid;
• a remixer (245) connected to the separator and to the heat collector unit, the remixer adapted to add a part of the antifreeze agent removed from by the separator back into the heat transfer fluid;
• a first temperature sensor (275) configured to monitor the temperature of the incoming air, the first temperature sensor located upstream of the heat delivery unit (230);
• a second temperature sensor (280) configured to monitor a temperature of the heat transfer fluid;
• and
• a control unit (285) operatively connected with the separator (250), the remixer (245), and the first and second temperature sensors (275, 280),
• the control unit adapted to analyse current temperature data provided by the first and second temperature sensors (275) and order i) the separator to remove the amount of the antifreeze agent from the heat transfer fluid, and ii) the remixer to add the part of the antifreeze agent to the heat transfer fluid, based at on the analysis of the current temperature data,
• wherein the heat collector unit i) delivers heat to incoming air by outgoing air heating the heat transfer fluid, and ii) transfers the heat from the heat transfer fluid to transfer to warm incoming air,
• wherein said control unit controls a current level of the antifreeze agent in the heat transfer fluid by ordering the remixer to add the part of the antifreeze agent to the heat transfer fluid when the current level is a predetermined amount lower than a wanted level, the wanted level based on avoiding freezing of the heat transfer fluid based on the monitored temperature of the incoming air, and
• wherein the wanted level is based on avoiding freezing of the heat transfer fluid based on i) the monitored temperature of the incoming air, ii) a freezing point of the heat transfer fluid, and iii) the monitored temperature of the heat transfer fluid,
• wherein the control unit, in the analysis of the current temperature data, is adapted to further analyse long-term statistics over relations between the monitored incoming air temperature, previously chosen levels of the antifreeze agent associated with the monitored temperature of the incoming air, and a resulting temperature of the heat transfer fluid for a local installation the long-term statistics being based on actual monitored incoming air temperature values and the monitored resulting temperature of the heat transfer fluid for the local installation in the operation of the heat exchange system of the ventilation system.