Still cold - but our JAHUS is warm inside

Progress:
The temperature is still below -10C and our ventilation aggregate stops working once every 24 hours (the rotating heat exchanger stops rotating and the motor makes a wird noice). The ventilation team has contacted the vendor (in Sweden) and say they will try to send someone over to finish the other work tomorrow (Wednesday, January 6th).

The second picture shows the outside part of the heatpump and the ice that has started to build underneath the heatpump. At the end of this blog post I have also included some pictures of the ice and condensated water that causes trouble inside the house (because air below 0C flows through pipes without isolation). When the team looked at it, they promised to fix it (but it hasn't happened yet).

I have included some of the temperature measurements below to illustrate how the different settings affect the supply of fresh air to the living room and the temperature of the exhaust air. For those of you who are above average interested, I have also included some comments about the different measurements etc.

The first columns in the report represent the input variables:

• Outside temperature: measured on the property, but away from the house (and hence as exact as possible with normal equipment)


• Heatpump: temperaturesetting on the heatpump (it tries to produce air at this temperature)


• Fan: a "1" means that the fan is running - pulling hot air from the area above the heatpump and inserting it into the airflow from the ventilation aggregate (after the heat exchanger)


• Ventilation aggregate: a "1" means minimum effect and a "2" means normal effect. "3" is maximum effect, but was not used during these tests

The next columns represent the results:

• Input air: this is the temperature of the fresh air that the ventilation systems sends out in the living room (after the heat exchanger and after the heated air from the heatpump has been added)


• Exhaust air: this is the temperature of the "used" air that leaves the house. When we lived in a "nei hus" ("no house") the temperature of the air leaving the house was 20C, but with the heat exchanger - the results show that we have managed to lower the temperature by as much as 26.9C (to -6.9C)


• Delta: shows a calculated difference between the outside temperature and the exhaust air (the lower values are the best - because we manage to transfer most of the energy from the exhaust air to the incomming fresh air)

Findings:

1. The heat exchanger works as expected (except for the stops mentioned earlier): The Delta is between 5 and 14C. When there is -18C outside, we send exhaust air of only -6.9C out of the house (Delta = 11.1C)


2. When the fan is off - the temperature the system supplies to the livingroom is below 10C and we therefore decided not to include those measurements


3. When it is below -10C it seems as though there is now effect of increasing the teperature setting of the heatpump. It probably runs at maximum effect anyways and even a setting of 40C would not make a difference.


4. When the outside temperature falls - the effect of the heat exchanger falls (the Delta temperature increases)
   
5. When the aggregate runs on normal effect (2) the volume of air flowing through the system is higher and the temperature of the air to the livingroom is therefore lower. When the temperature of the exhaust air is lower (due to the effect mentioned above), the exchanger is able to cool it down more than the tests with the aggregate running at low effect (1).