1. Improving thermal and visual user comfort in very low energy buildings
What is the right combination of insulation thickness , heat capacity , and other passive energy saving measures to achive better themal conformt ??
Answer : Well the answe is not unique since there are too many parameters influence the building dynamic response under real weather condition.
Many studies have been focused on the reduction of energy losses , peak load control and energy saving. Nevertheless, very few studies were realized adressing both insulation and thermal
Comfort perspectiv.
But, that’s why im here . Im Negrea Liviu and im here to present the improving thermal and visual user comforet in very low energy buildings !
Alexandra DANU
Liviu Andrei NEGREA
Vladimir TANASIEV
Adrian BADEA
Horia NECULA

2. Index 1. About Passive Houses 2. Passive House UPB: case study
3. HVAC system
4. Simulations
5. Measurements
6. Interior comfort
As for my index im gonna start with a bit of historty regarding the concept of passive houses
Im going to move on and talk abou the case study that I’ve did , the systems that helped me to achive a better thermal comfort
Some simulation on the system
Measureamnts…
Ofc the interior conform with some graphics
And to sum up to the ideea , conclusion.

3. About Passive Houses
“Passivhaus” - energy-efficient standard for buildings
Passive house criteria :
Specific space heating demand should not exceed 15 kWh/m2yr;
Primary energy demand should not exceed 120 kWh/m2yr for all energy services (heating, cooling, hot water and electric appliances);
Air exchange between the interior and the exterior of the building should not exceed 0.6 h-1 at a difference of 50 Pa.
The “passivhaus” term refers to an energy-efficient standard for buildings, developed and implemented by the Passivhaus Institute from Germany . The founders were Wolfgang Feist and Bo Adamson who started to investigate how buildings could be designed in more sustainable and energy efficient way.
A house can be certifited as a low energy building if meets the fowllowing criteria : !
Using this standard combined with a very efficient heating, ventilation and air conditioning (HVAC) system based on renewable energy sources, the energy demand for heating has been reduced by 80% compared with conventional buildings and by 75% compared with new buildings
Energy demand - 80% conventional buildings % new buildings

4. Passive House UPB: case study
East Building – case study & laboratory research
West Building– conferences
W – geothermal HP
E - HVAC
Occupancy – 40% living room , 3% kitchen
U-value opaque
elements 0.15 W/m2/K
U-value of the windows
0.6 W/m2/K
Applying the Passivhaus Standards, a low-energy building was built in UPB.
The house is divided in 2 small houses : West Part – where usually are taking places conferences and important discussions. The system is working under geothermal heat pumps setups .and a East part – where case study have been made , which is used for reaseach purposes , is equiped with a HVAC system.
Due to the occupancy distribution and no cooking activities, the living room counts for more than 40% , kitchen for just 3% and that makes it different from a standard house. During the night the house is inhabited , The materials used for the envelope and the windows have high thermal performances
The U-values for the opaque elements (roof, exterior walls and ground floor) are lower than 0.15 W/m2/K. The exterior triple-glazing windows have a U-value of 0.6 W/m2/K and total solar absorbance coefficient (G-value) of 50%.
Passive House, University Politehnica of Bucharest

5. Data acquisition and HVAC system
Earth-Air
Air-Air
Electric air heater resitance of 2.4kW
Photovoltaic system of 3 kW
Data acquisition – Wire and wireless sensons
Now ,as we were talking about the East House and the system this part is equiped with … the HVAC is the solution that we came up with , and is composed of a two exchangers : earth to air heat exchanger and an air to air heat recovery unit. The double flow mechanical ventilatio nis realized with the help of fans.
For the cold season we use and electric air heater resitance of 2.4kW
Hot water is producewd using a solar panel mounted on the roof
A part of the Electricity used in the house is given by a photovoltaic system 3 kW, connected to the grid.
The data acquisition system collets throught wire and wireless sensors parameters such as : outiste temp,air flow , interior CO2 concentration, humidity,luminosoty,solar radion.
There are 8 wired sensors that mesure the airflow temperature from HVAC route
And 5 wireless that measure the temperature , humidity, and luminosity from each room , but im going to presint this is the next slide.
T1- outside Tg – ground – T2 – exit temp from the canadian well T3 – exchanger T5- inside temp
HVAC system

6. Data acquisition and HVAC system
There are 5 wireless sensors (named W1 to W5) which collect data regarding temperature, luminosity and humidity parameters. Their positioning is shown in Fig. 5.
The power consumption is monitored through 7 energy meters which measures the following groups of appliances:
E1 – Lights
E2 – Living room (radiant panel and appliances)
E3 – Kitchen appliances
E4 – Monitoring system (sensors, data-logger, acquisition system)
E5 – Electric resistance
E6 – MVHR unit (inside fans)
E7 – Bathroom (radiant panel)
The data logger records the data received from sensors. The information is harvested every 5 minutes and transmitted through serial connection to the server where is stored in a data base.
The Smart Building Controller (SBC) is used to centralize and simplify the monitoring and management of the building.
Wi-fi data acquisition

7. Simulations and discussions
The simulations were made using Energy Plus 7 and Open studion plugin for google sketch up
,during a whole year. Starting from october.
The green color represent the heating energy consumption – kWh/m^2 yr using the HVAC system
In order to see the energy consumption of the house we made 2 simulations :
in free-running mode where no mechanical heating or cooling is available
1. The free mode simulation shows a variation of the interior temperature between 6 – 28 in the summer period.
2. House equipped with HVAC with imposed limits of interior temperature.
2. AS you can see the interior temperatur is maintained between 20 – 25 degree using HVAC sysyem
With estimated energy consumption for heating : 2080 kWh and for cooling 1987 kWh.
The variation of the energy demand and the indoor temperature for the Living room area with and without HVAC system during one year

8. Mesurements and discussions
The passive house is monitored continuous since 2012 and the nalyzed data were collected over an entier year period.
AS you can see , the graphic shows us the outside and inside average temperature .
There were sometime when we had -16 degrees and we used the electric air heater more to had a good thermal comfort inside the building.
In the heating period the interior temp was mantained between 20 – 22 degree by varying the power consumption used by the electric air heater.
While in the summer period with the help of the HVAC system equipped with fans , the interior temp varied 18 – 30. with minum of energy requirments.
Variation of inside average temperature in the passive house of UPB during one year

9. Evolution of the HVAC temperatures on 22nd of July 2014
Interior comfort
As you can see , during the warm season the house is passing through various stages.
We made this simulation on an entire day , 22 july , when the average temp during summer days was 26 degrees.
We got the data from every sensors of each room and we came up with this brilliant graphic that allows us to see the temp movement inside the house.
The solar radion was high and had a big influence on the inside temp through the large windows from the south of the house on the int temp.
Even if the radion was super high, and the treadline was supposed to be followed but with our HVAC system we managed to keep it under good thermal conditions. The figure with more green shows us the the exact values of the entrace temp inside the house.
So with the orange color we have the entrace air temp who is way much lower than the blue color , the represents the outside temperature.
Evolution of the interior and exterior temperature on 22nd of July 2014
Evolution of the HVAC temperatures on 22nd of July 2014

10. Conclusions
The purpose of simulations was to choose the right strategy for achieving thermal comfort with minimal energy consumption.
Using the right amount of energy consumption for heating and ventilation, the house could be maintained in the winter in the imposed limits and consumed under 15 kWh/m2 . yr.
Choosing the right scenario leads us to the desired interior comfort.

11. References
Plus Energy Houses - POLITEHNICA Plus Energy Building, A. Badea, CIEM 2011, Bucharest, 2011
EnergyPlus Documentation, version 7.0.
G. E. Vlad, C. Ionescu, H. Necula, A. Badea, Simulation of an air heating/cooling system that uses the ground thermal potential and heat recovery, U.P.B. Sci. Bull., Series C, Vol. 75, Iss. 3, 2013 ISSN
HVAC Solutions for the passive houses from University POLITEHNICA of Bucharest, C. IONESCU, CIEM 2011, 3-4 November 2011, Bucharest
V Tanasiev., Contributions to the development of intelligent building concept with high energy efficiency, PhD thesis, 2012
V. Tanasiev, B. Carutasiu, A. Badea, Dynamic simulation of energy consumption for a passive house in Romanian climate conditions,– CIEM 2013, Bucharest
B. Carutasiu, V. Tanasiev, C. Ionescu, A. Badea, Nearly zero energy buildings in temperate continental climate, COFRET, 2014, Paris

12. Acknowledgment
The work has been funded by the Sectorial Operational Programme Human Resources Development of the Ministry of European Funds through the Financial Agreement POSDRU/159/1.5/S/
This paper work was funded by program “Parteneriate” in priority areas – PN II carried out by MEN-UEFISCDI, project No. 47/2014 and Erasmus+ through financial agreement RO01-KA

13. Thank you for your attention !