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Heat Exchanger and Outdoor Air Mixer

I have been using the "heatExchanger:AirToAir:SensibleAndLatent" object and the "OutdoorAir:Mixer" object in EnergyPlus and I have started to realised things have been going a little bit strange with this combination. When I look at the temperatures flowing through these two objects I get some odd results. I have a DOAS system and so the return air from the zones should not mix or come into contact with the supply air, other than through the heat exchanger. In EnergyPlus however if you have a heat exchanger then you must have an outdoor air mixer (I believe and am happy to be corrected on this). The temperature of the supply air coming into the heat exchanger and the air leaving the heat exchanger are as I would expect. However, when the air enters the outdoor air mixer from the heat exchanger it mixes with the return air from the zones and the temperatures leaving the OAM and into the AHU change, they go up in the winter and down in the summer, over stating how effective the heat exchanger actually is.

image description

My question is: How can I stop this from happening? Is there something in the controller than can stop the air mixing in the outdoor air mixer, is there something in the "heatExchanger:AirToAir:SensibleAndLatent" object to stop this from happening?

All and any help as always greatly appreciated.

Heat Exchanger and Outdoor Air Mixer

I have been using the "heatExchanger:AirToAir:SensibleAndLatent" object and the "OutdoorAir:Mixer" object in EnergyPlus and I have started to realised things have been going a little bit strange with this combination. When I look at the temperatures flowing through these two objects I get some odd results. I have a DOAS system and so the return air from the zones should not mix or come into contact with the supply air, other than through the heat exchanger. In EnergyPlus however if you have a heat exchanger then you must have an outdoor air mixer (I believe and am happy to be corrected on this). The temperature of the supply air coming into the heat exchanger and the air leaving the heat exchanger are as I would expect. However, when the air enters the outdoor air mixer from the heat exchanger it mixes with the return air from the zones and the temperatures leaving the OAM and into the AHU change, they go up in the winter and down in the summer, over stating how effective the heat exchanger actually is.

image description

My question is: How can I stop this from happening? Is there something in the controller than can stop the air mixing in the outdoor air mixer, is there something in the "heatExchanger:AirToAir:SensibleAndLatent" object to stop this from happening?

All and any help as always greatly appreciated.

Heat Exchanger and Outdoor Air Mixer

I have been using the "heatExchanger:AirToAir:SensibleAndLatent" object and the "OutdoorAir:Mixer" object in EnergyPlus and I have started to realised things have been going a little bit strange with this combination. When I look at the temperatures flowing through these two objects I get some odd results. I have a DOAS system and so the return air from the zones should not mix or come into contact with the supply air, other than through the heat exchanger. In EnergyPlus however if you have a heat exchanger then you must have an outdoor air mixer (I believe and am happy to be corrected on this). The temperature of the supply air coming into the heat exchanger and the air leaving the heat exchanger are as I would expect. However, when the air enters the outdoor air mixer from the heat exchanger it mixes with the return air from the zones and the temperatures leaving the OAM and into the AHU change, they go up in the winter and down in the summer, over stating how effective the heat exchanger actually is.

image description

My question is: How can I stop this from happening? Is there something in the controller than can stop the air mixing in the outdoor air mixer, is there something in the "heatExchanger:AirToAir:SensibleAndLatent" object to stop this from happening?

All and any help as always greatly appreciated.