quantitative and qualitative evaluation of indoor thermal...

Quantitative and Qualitative Evaluation Of Indoor Thermal and Air Quality In Two Office Buildings

Panagiota Antoniadou, Christina Konstantinidou*, George Mantikas, Agis M. Papadopoulos

Process Engineering Design Laboratory, School of Mechanical Engineering, Aristotle University Thessaloniki, Greece

47. Međunarodni kongres i izložba o KGH, Beograd, 30.11–2.12.201647th International HVAC&R Congress and Exhibition, Belgrade, Nov.30–Dec.2 2016

IntroductionThe annual increase of the energy consumption outlines the need to upgrade the existing building stock, as depicted from a variety of European Directives (2002/21EU, 2012/27/EU, 2010/31EU), even before the introduction of the “20-20-20” targets.

The existing building stock is responsible for 36% of the final energy consumption, therefore immediate measures should be applied.


IntroductionThe need to create a safe and comfortable work environment is fundamental for the building industry, as they affect the occupants productivity and well-being.

The commonly used International Standards for the evaluation of thermal environments are ISO 7730-2005, ASHRAE 55-2013 and EN 15251-2007.

Main objectives of this study are the evaluation of:

› indoor air conditions and

› occupants’ perception of indoor conditions


Buildings’ Description› Both under evaluation buildings are office buildings and are located in Thessaloniki, Greece.

› The climate of the area is Mediterranean (Csa on the Koeppen scale) with moderately cold winters and warm summers. With respect to the national energy regulation, they belong to the 3rd coldest climate zone (Zone C).


Buildings’ Description- Technical Service of Pylaia-Hortiati’s MunicipalityBuilding Characteristics

› Construction period 1998

› Efficient Insulated

› Main orientation North-West, with opening in all surfaces

› Double glazed, aluminum framed windows

› Internal blinds

› Fluorescent tubes

HVAC Characteristics

› Central gas boiler that feeds radiators

› Local heat pumps (room air-conditioners)

› Operational schedule 7.00am -4.00pm


Buildings’ Description- Former Town Hall of Pylaia- Hortiati’s Municipality

Building Characteristics

› Two building construction, connected with external corridor

› Construction period 1995

› Efficient Insulated

› Main orientation North-West, with opening in all surfaces

› Tinted, double glazed, aluminum framed windows

› Fluorescent tubes and autonomous artificial lighting in corridors

HVAC Characteristics

› Both heating and cooling by means of geothermal systems

› Extra local heating means (e.g. electric heaters)

› Operational schedule 7.00am -4.00pm


In situ evaluationFor the determination of the indoor environmental conditions the under monitoring parameters are:

› Temperature and relative humidity levels

› CO2 levels

› PPD & PMV indexes

The measurement period is specified in the winter, for a 7 days period in every case.


In situ evaluation-Temperature ConditionsTechnical Service of Pylaia-Hortiati’s Municipality

› Office 1: a 2nd floor corner office, with three external surfaces and openings on NW & SE façades.› Office 2: a 2nd floor corner office, with three external surfaces and openings on NW & NE façades.› Office 3: a 1st floor corner office, with three external surfaces and openings on NW & SE façades.› Office 4: a 1st floor corner office, with three external surfaces and openings on NW & NE façades.› Office 5: a ground floor corner office, with two external surfaces and openings on NW & NE façades.


During weekDuring weekend

In situ evaluation-Temperature ConditionsFormer Town Hall of Pylaia-Hortiati’s Municipality

Building Front› Office 1: a 1st floor corner office, with two external surfaces and openings on N & NW façades.› Office 2: a 2nd floor corner office, with two external surfaces and openings on N & NW façades.› Office 5: a 2nd floor corner office, with two external surfaces and openings on N & NE façades.› Office 7: a ground floor intermediate office, with an external surface and openings on NW façade.

Building Back› Office 3: a ground floor intermediate office, with an external surface and openings on NW façade.› Office 4: a 1st floor intermediate office, with an external surface and openings on the NW façade.› Office 6: a ground floor intermediate office, with an external surface and openings on the NW.› Office 8: a 1st floor intermediate office, with an external surface and openings on the NW façade.


In situ evaluation-Temperature ConditionsFormer Town Hall of Pylaia-Hortiati’s Municipality


During weekDuring weekend

In situ evaluation-CO2 Levels

Former Town Hall of Pylaia-Hortiati’s Municipality


Technical Service of Pylaia-Hortiati’s Municipality

In situ evaluation-Thermal Comfort

Former Town Hall of Pylaia-Hortiati’s Municipality


Technical Service of Pylaia-Hortiati’s Municipality

Qualitative Evaluation of Indoor Environment ConditionsA revealed preference survey is conducted to determine indirect valued conditions and goods in case of the Office

buildings.Methodological Approach› Evaluation of criteria and potential parameters› Construction of questionnaire:

– Individual information– Thermal comfort conditions– Occupants’ attitude towards the building envelop and the HVAC systems

› Data collectionThe collected sample has an error of 8% and confidential level of 95% based on the population of thebuildings.

› Data analysisAn inferential statistical analysis is implemented to specify the parameters that are correlated with theoccupants’ expression of complaints on indoor conditions and the perceived indoor conditions during winter.


Qualitative Evaluation of Indoor Environment ConditionsInferential Statistical AnalysisThe respondents were asked to determine whether or not do they express complaints on heating, cooling,

ventilation, natural and artificial lighting, noise and work environment conditions and determine theirperception of indoor conditions during winter in a Likert scale from 1 (unsatisfied) to 7 (satisfied).

Due to the nature of the data a non-parametric Mann-Whitney U statistical analysis is conducted and the resultsare depicted in the following Table with a confidential interval of 99% in almost all cases.


Z Asymp. Sig. (2-tailed)Indoor temperature conditions during winter - Heating Complaints -2.234 0.025Artificial lighting during winter - Heating Complaints -2.964 0.003Total lighting during winter -Heating Complaints -2.695 0.007Natural lighting during winter - Natural Lighting Complaints -2.440 0.015Artificial lighting during winter - Natural Lighting Complaints -2.709 0.007Total lighting during winter -Natural Lighting Complaints -2.703 0.007Total comfort satisfaction during winter- Natural Lighting Complaints -2.328 0.020Glare due to natural lighting during winter -Noise Complaints -2.056 0.040Total noise during winter- Noise Complaints -2.042 0.041Total noise during winter- Work Environment Complaints -3.139 0.002Total comfort satisfaction during winter- Work Environment Complaints -2.038 0.042

Qualitative Evaluation of Indoor Environment ConditionsInterpretation-Complaints on HeatingThe analysis outlines that the respondents who do not express complaints on heating, determine the perceived

indoor temperature, artificial lighting and total lighting conditions during winter as satisfactory.


Qualitative Evaluation of Indoor Environment ConditionsInterpretation-Complaints on Natural LightingRegarding, natural lighting complaints, is demonstrated that, as expected, the more unsatisfied the respondent

are concerning natural, artificial, total lighting conditions and total comfort sensation during winter, the morecomplaints on the matter are expressed.


Qualitative Evaluation of Indoor Environment ConditionsInterpretation-Complaints on NoiseThe statistical testes deduce that complaints on noise are expressed when the occupants are neutral to slightly

satisfied with the indoor glare due to natural lighting during the winter and while the total noise levels aredescribed as neutral and unsatisfied.


Qualitative Evaluation of Indoor Environment ConditionsInterpretation-Complaints on Work EnvironmentThe analysis states that the more unsatisfied the total comfort sensation of the occupants’ and total noise levels

during winter are described, the more complaints concerning the work environment conditions are expressed.


Conclusions› The in situ evaluation outlined that in both cases the indoor environment conditions can be characterized as

preferable for the winter period, as the majority of the under evaluation parameters are in desirable ranges. In both cases the indoor temperature and PMV levels correspond to values that state healthy indoor conditions. However, care should be expressed on ventilation, as the CO2 levels on certain cases reach values over the recommended limits, affecting the occupants’ health. Therefore, proper ventilation strategies should be applied.

› The inferential statistical analysis demonstrated the indoor parameters that affect the occupants’ expression of complaints. The analysis depicted that the heating, natural lighting, noise and work environments complaints expressed by the occupants are statistically important correlated with a variety of perceived indoor environment conditions during winter.

› The determination of indoor conditions and the linkage of the perceived conditions to the expression of complaints by the occupants, can lead to an initial understanding of the parameters that affect the occupants and create an approach where both the structural and occupants’ characteristics are implemented.


Quantitative and Qualitative Evaluation Of Indoor Thermal and Air Quality In Two Office Buildings

Thank you for your attention!

Christina Konstantinidou [email protected] Antoniadou [email protected]


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