Final comfort model selected:
Based on various analysis of material(included below) the Humphreys and Nicol comfort equation will be used:
Tc=11.9 + 0.534 To (for free running buildings)
and in episode 3 :
Tc= 23.9 + 0.295(To-22) exp(-[To-22)/(24root2)]squared} (for heated or cooled buildings)
To = monthly mean outdoor temperature (oC)
Tc = comfort temperatre (oC)
Tc=11.9 + 0.534 To (for free running buildings)
and in episode 3 :
Tc= 23.9 + 0.295(To-22) exp(-[To-22)/(24root2)]squared} (for heated or cooled buildings)
To = monthly mean outdoor temperature (oC)
Tc = comfort temperatre (oC)
ANALYSIS OF COMFORT MODES:
ASHRAE'S STANDARD 55 / EN15251
WHICH ONE TO USE?
'Current international comfort standards still embody black and white definitions of AC (air conditioned) and NV (naturally ventilated) buildings.'
'A problem for calculation of the neutral temperature in a variable environment such as a free-running building is that it presents a ‘moving target’. It is continually changing as people adapt to their changing environment by modifying their clothing and adjusting their attitude the environment.'
4. Calculating the exponentially weighted running mean outdoor temperature The adaptive approach to predicting neutral temperatures in
free-running buildings has been to relate the neutral temperature to a measure of outdoor temperature. In the early analysis of Humphreys [20] the index of outdoor temperature was the monthly mean of the outdoor temperature. The values were obtained from published world tables of meteorological data then available. He showed that the neutral temperature was related more closely to the monthly mean temperature than to either the monthly mean maximum or monthly mean minimum temperatures. The monthly mean temperature was taken to be the average
of the monthly mean maxima and the monthly mean minima. The tabulated monthly mean is unsatisfactory for two reasons:
The value of the monthly mean is open to misinterpretation (is it the historical mean? Or is it the mean of the preceding month or the present calendar month?)
The temperature can be very variable within a month, resulting in changes in the neutral temperature through clothing changes, use of fans etc.
'The experience of comfort surveys is that the neutral temperature within a free-running building is linearly related to the outdoor temperature. Analysis of the SCATs data for freerunning buildings confirms linearity '
Citation: [Nicol & Humphreys 2010]
REFERENCE: Nicol F., Humphreys M., 2010. Derivation of the adaptive equations for thermal comfort in free-running buildings in European standard EN15251. Building and Environment. VOLUME 45. pp 11–17
'A problem for calculation of the neutral temperature in a variable environment such as a free-running building is that it presents a ‘moving target’. It is continually changing as people adapt to their changing environment by modifying their clothing and adjusting their attitude the environment.'
4. Calculating the exponentially weighted running mean outdoor temperature The adaptive approach to predicting neutral temperatures in
free-running buildings has been to relate the neutral temperature to a measure of outdoor temperature. In the early analysis of Humphreys [20] the index of outdoor temperature was the monthly mean of the outdoor temperature. The values were obtained from published world tables of meteorological data then available. He showed that the neutral temperature was related more closely to the monthly mean temperature than to either the monthly mean maximum or monthly mean minimum temperatures. The monthly mean temperature was taken to be the average
of the monthly mean maxima and the monthly mean minima. The tabulated monthly mean is unsatisfactory for two reasons:
The value of the monthly mean is open to misinterpretation (is it the historical mean? Or is it the mean of the preceding month or the present calendar month?)
The temperature can be very variable within a month, resulting in changes in the neutral temperature through clothing changes, use of fans etc.
'The experience of comfort surveys is that the neutral temperature within a free-running building is linearly related to the outdoor temperature. Analysis of the SCATs data for freerunning buildings confirms linearity '
Citation: [Nicol & Humphreys 2010]
REFERENCE: Nicol F., Humphreys M., 2010. Derivation of the adaptive equations for thermal comfort in free-running buildings in European standard EN15251. Building and Environment. VOLUME 45. pp 11–17
'This paper investigates how mixed-mode (MM) ventilation affects occupant comfort by presenting results from a longitudinal field study within an academic office building from a tertiary educational institution in sub-tropical Sydney, Australia. The building automatically switches into air-conditioned (AC) mode whenever indoor temperatures exceed 25 °C. Coincident indoor and outdoor climate measurements along with 1359 subjective comfort questionnaires were collected. Thermal sensations during natural ventilation did not conform to those predicted using Fanger’s PMV-PPD [1]. Differences in thermal perception were also apparent between these two modes. Within AC mode, a PMV = +1 environment elicited much ‘warmer-than-neutral’ thermal sensations than the same PMV = +1 environment within naturally-ventilated (NV) mode, suggesting thermal subjective perceptions were affected by the building’s mode of operation over and above the objective indoor climatic conditions. These discrepancies emphasize the complexity of thermal perception and the inadequacy of using PMV models to describe occupant comfort in MM buildings. ASHRAE’s Standard 55 [2] currently classifies MM buildings as AC buildings, and as such, limits the operation of these buildings to the more restrictive PMV-PPD range of indoor thermal conditions. In contrast, EN15251 [3] permits the more flexible adaptive comfort standard to be applied to buildings operating under NV mode. Results from this study favour EN15251’s application of the adaptive comfort model instead of PMV-PPD to MM buildings when they are operating in NV mode.'
'
This paper investigates how occupant comfort is affected in a building that switches between AC and NV environments, i.e. in a MM building. Current international comfort standards still embody black-and-white definitions of AC and NV buildings. If a building is AC, then it typically doesn’t have operable windows. According to ASHRAE Standard 55 [2] if a building is NV, then it doesn’t have any mechanical cooling/heating systems, but typically has operable windows. However, the real world is not so simple. The most current version of ASHRAE Standard 55-2010 misclassifies MM buildings as AC and in doing so, not only limits the operation of such buildings to the more restrictive PMV-PPD range of indoor thermal conditions, but fails to maximise the energy saving potential of MM buildings. By comparing both observed and predicted thermal sensation votes recorded in AC and NV modes, the adaptive comfort model was found to be applicable to the MM building, especially during times of natural ventilation. In evaluating the current definition and scope of the adaptive comfort standards in ASHRAE 55-2010 and EN15251-2007, this paper provides evidence that MM buildings could in fact be defined as NV, with operable windows and supplemental cooling/heating during peak periods. Whilst this study represents one particular change-over MM case study in Sydney, Australia, many other types of MM buildings exist around the world, e.g. concurrent (where air-conditioning and operable windows are utilised in the same space and at the same time) and zoned (when passive and mechanical strategies occur at the same time but in different zones within the building). These findings help shed light as to how MM buildings, especially with change-over control strategies, should be categorised in future comfort standards. However, as more MM buildings are likely to be built in the future, more field studies (using different control strategies and in different climates) are needed to fully understand how MM ventilation affects occupant comfort and whether a new MM comfort standard should be established.'
citation: [Deuble & de DeaR, 2012]
reference: Deuble M.P., de Dear R.J., 2012. Mixed-mode buildings: A double standard in occupants’ comfort expectations. Building and Environment. Volume 54. pp 53-60
'
This paper investigates how occupant comfort is affected in a building that switches between AC and NV environments, i.e. in a MM building. Current international comfort standards still embody black-and-white definitions of AC and NV buildings. If a building is AC, then it typically doesn’t have operable windows. According to ASHRAE Standard 55 [2] if a building is NV, then it doesn’t have any mechanical cooling/heating systems, but typically has operable windows. However, the real world is not so simple. The most current version of ASHRAE Standard 55-2010 misclassifies MM buildings as AC and in doing so, not only limits the operation of such buildings to the more restrictive PMV-PPD range of indoor thermal conditions, but fails to maximise the energy saving potential of MM buildings. By comparing both observed and predicted thermal sensation votes recorded in AC and NV modes, the adaptive comfort model was found to be applicable to the MM building, especially during times of natural ventilation. In evaluating the current definition and scope of the adaptive comfort standards in ASHRAE 55-2010 and EN15251-2007, this paper provides evidence that MM buildings could in fact be defined as NV, with operable windows and supplemental cooling/heating during peak periods. Whilst this study represents one particular change-over MM case study in Sydney, Australia, many other types of MM buildings exist around the world, e.g. concurrent (where air-conditioning and operable windows are utilised in the same space and at the same time) and zoned (when passive and mechanical strategies occur at the same time but in different zones within the building). These findings help shed light as to how MM buildings, especially with change-over control strategies, should be categorised in future comfort standards. However, as more MM buildings are likely to be built in the future, more field studies (using different control strategies and in different climates) are needed to fully understand how MM ventilation affects occupant comfort and whether a new MM comfort standard should be established.'
citation: [Deuble & de DeaR, 2012]
reference: Deuble M.P., de Dear R.J., 2012. Mixed-mode buildings: A double standard in occupants’ comfort expectations. Building and Environment. Volume 54. pp 53-60
http://smap.cbe.berkeley.edu/comforttool
ASHRAE 55-2004
https://www.ashrae.org/
This model applies especially to occupant-controlled, natural conditioned spaces, where the outdoor climate can actually affect the indoor conditions and so the comfort zone
Behavioral,
Physiological
Psychological.
DE DEAR -BRAGER
http://www.cbe.berkeley.edu/research/other-papers/de%20Dear%20-%20Brager%201998%20Developing%20an%20adaptive%20model%20of%20thermal%20comfort%20and%20preference.pdf
https://www.ashrae.org/
This model applies especially to occupant-controlled, natural conditioned spaces, where the outdoor climate can actually affect the indoor conditions and so the comfort zone
Behavioral,
Physiological
Psychological.
DE DEAR -BRAGER
http://www.cbe.berkeley.edu/research/other-papers/de%20Dear%20-%20Brager%201998%20Developing%20an%20adaptive%20model%20of%20thermal%20comfort%20and%20preference.pdf
Fanger’s PMV (Predicted Mean Vote) (Fanger, 1972) model forms the basis for ASHRAE standards for thermal comfort
It is a deterministic heat balance model based on empirical studies done in artificial climate chambers on college students engaged in sedentary activity, leading to several systematic discrepancies. Contrarily, Fanger (1982) finds no evidence of adaptation other than in clothing; hence he prescribes uniform comfort conditions throughout the world. The consequences of these uniform comfort standards for all types of buildings and climates were bitterly criticised, especially in the wake of the Kyoto Protocol and anthropogenic climate changes.
@font-face { font-family: "Times"; }@font-face { font-family: "Cambria"; }p.MsoNormal, li.MsoNormal, div.MsoNormal { margin: 0cm 0cm 0.0001pt; font-size: 12pt; font-family: "Times New Roman"; }a:link, span.MsoHyperlink { color: blue; text-decoration: underline; }a:visited, span.MsoHyperlinkFollowed { color: purple; text-decoration: underline; }div.Section1 { page: Section1; }
Indraganti, Madhavi (2010, April 7). Adaptive Model of Thermal comfort. SciTopics. Retrieved December 17, 2013, from http://www.scitopics.com/Adaptive_Model_of_Thermal_comfort.html
FREERUNNER
http://www.archiphysics.com/programs/freerunner/freerunnner.htm
The program FreeRunner calculates the comfort level in a free running building that uses only solar gain for heating. The interface in this program is a series of sliders that the user manipulates in order to fine-tune the different components of a building.
SOLARSHOEBOX
USING SOLARSHOEBOXThere are eight main parameters that can be changed when using SolarShoeBox. These parameters can be done is steps with intermediate simulation runs by Energyplus. It takes about 6 seconds for Energyplus to calculate the results and to refresh the graph allowing many iterations to be done very quickly. All of these steps can be performed before the design process begins and should be the basis for the building design. The student should use this information similarly to using the information of how big a column must be to hold up a building; the combination of components given by SolarShoeBox are necessary for their building to be comfortable while using no fossil fuels. It is important for the student to imagine, for example, that a wall with a window that is 50% of the area of the wall does not have to be a single window, but can be many windows arranged in an infinite number of ways. Using the column analogy, a thin steel pipe or a heavy timber post might perform in a similar way but are aesthetically and sensorially very different.
ll of the following steps can be done out of order and revisited at any time in the process. The order given is usually the first pass as the student attempts to create a comfortable indoor environment
It is a deterministic heat balance model based on empirical studies done in artificial climate chambers on college students engaged in sedentary activity, leading to several systematic discrepancies. Contrarily, Fanger (1982) finds no evidence of adaptation other than in clothing; hence he prescribes uniform comfort conditions throughout the world. The consequences of these uniform comfort standards for all types of buildings and climates were bitterly criticised, especially in the wake of the Kyoto Protocol and anthropogenic climate changes.
@font-face { font-family: "Times"; }@font-face { font-family: "Cambria"; }p.MsoNormal, li.MsoNormal, div.MsoNormal { margin: 0cm 0cm 0.0001pt; font-size: 12pt; font-family: "Times New Roman"; }a:link, span.MsoHyperlink { color: blue; text-decoration: underline; }a:visited, span.MsoHyperlinkFollowed { color: purple; text-decoration: underline; }div.Section1 { page: Section1; }
Indraganti, Madhavi (2010, April 7). Adaptive Model of Thermal comfort. SciTopics. Retrieved December 17, 2013, from http://www.scitopics.com/Adaptive_Model_of_Thermal_comfort.html
FREERUNNER
http://www.archiphysics.com/programs/freerunner/freerunnner.htm
The program FreeRunner calculates the comfort level in a free running building that uses only solar gain for heating. The interface in this program is a series of sliders that the user manipulates in order to fine-tune the different components of a building.
SOLARSHOEBOX
USING SOLARSHOEBOXThere are eight main parameters that can be changed when using SolarShoeBox. These parameters can be done is steps with intermediate simulation runs by Energyplus. It takes about 6 seconds for Energyplus to calculate the results and to refresh the graph allowing many iterations to be done very quickly. All of these steps can be performed before the design process begins and should be the basis for the building design. The student should use this information similarly to using the information of how big a column must be to hold up a building; the combination of components given by SolarShoeBox are necessary for their building to be comfortable while using no fossil fuels. It is important for the student to imagine, for example, that a wall with a window that is 50% of the area of the wall does not have to be a single window, but can be many windows arranged in an infinite number of ways. Using the column analogy, a thin steel pipe or a heavy timber post might perform in a similar way but are aesthetically and sensorially very different.
ll of the following steps can be done out of order and revisited at any time in the process. The order given is usually the first pass as the student attempts to create a comfortable indoor environment