AIR VENTILATION EFFECTIVNESS

Chosen Space: Conference / Board Room / Education Space

The space is for education and conference purposes therefore, will require a control of light, and thermal properties within the space in order to maintain a comfortable level within the room by utilising passive strategies.

The exisiting building form utilises cross-ventilation throughout the building, however, with the opeingings of the space not being controlled as well as the space having a large volume, cross ventilating the space is found difficult.

The form of the buildign is also not being fully utilised to its maximum potential as stagnant air is gathering towards the top of the space due to buoyency driven hot air rising and not having openings that allow the air to dispurse and create a continuation of air flow enhanced by stack ventialtion. Controlled opeings such as skylights or clerestory’s can help enhance the stack ventialtion potential inside the space.

Thermal Properties: The Wall and floor material build up uses concrete finish on the interieor in order to utilising thermal mass in the space, naturally using this strategy will assist in storing heat passivly during warmer periods and releasing heat during cooler periods. The dense quality of the finish conrete will store heat during the winter and slowly relese it when temperatures drop ensuring less need for active system using to heat a space (Simone, 2017).

Whereas, during the summer, radient temperature is absorbed lowing room temperature ensuring no need for additional cooling from active systems.

The WindRose shows that on the 20th July Predominant wind approach comes from the SouthWest reaching Velocity of up to 12 - 15 m/s at 1200 Hrs (Fig.X).

Comparing the results of the average velocity recorded in the occupied space to the CBE Thermal Comfort tool for a Conference / Board Room. Results show that thermal comfort with the velocity of the selected space do not comly with the CBE tool and that indoor themperatures are higher than expected.

The results are slightly hgher than the reccomended temperature required and therfore minimal active systems will need to be utilised via natrually sources energy such as solar gain.

Slight ammendments will need to be altered such as building orientation, window oeping side and window placement accross the building.

Stale / Stagnant Air in the Centre of the space at a low velocity of 0.08m/s0.16 m/s. Stagnant air measurig at a low velocity can cause slgith discomfort according to ‘Table 10.8 - Air Velocities and Thermal Comfort’ (Wiley, 2015) in the space as wel as damp when exposed to moisture and overheating from internal gains such as people.

South Facing WIndows recieve the most velocity in the room by achieveing a substantual 0.82m/s - 0.9m/s input from wind approach from the ‘South-West’ (Reffer to FIG. X).

Noticable and acceptable wind speed is achieved (Wiley, 2015).

However slows down very quickly due to the empty large space which does not assist the cross ventilation in the room.

Stagnant Air with a Velocity Between 0.0 m/s - 0.08 m/s shows no air flow is present inbetween windows. Winder openings will be needed to improve the cross ventilation without ustilising active ssystems.

Wind Output toward the North Facing Windows. Minimal Cross Veltilation is achieved reaching 0.65m/s Velocity however only at the window openings and not the more occupied spaces of the centre of the room.

Hot Air escape for ventialtion flow but slight restriction to the movment of air flow.

Sligh wind approach comes in from the South with minimal Velocity of 3 - 6 m/s. This is not enough to allow significantly impacting cross or stack ventilation throughout the space.

80% Opening alllows significant air flow however han cause high temperature drops during cooler climates.

Air Movement is Direct towards the openings and reaching wind speeds of up to 9 m/s - 12 m/s on 20th July at 1200Hrs. The direct wind speed will allow fresh air to enter the building and flow to assit buoyency driven stck ventilation and cross ventilation for continuous air flow and the renew of freh air.

Building Rotation: As an amendment the building is rotated towards the South-West in order to capture as much wind exposure as possible towards the South-West Facing Facade openings.

This Maximised the potential of Air Movement to enhance Cross-Ventilation.

The comparing of the reults of IESVE simulations of the Wind Velocity in the building to the CBE Thermal Comfort tool shows that the adaptations to the design comply with the CBE Thermal Tool and ASHRAE Standards 55-2020. The results are centralised within the comfort zone at a comfortable Operative Temperature of 25°C which complies with the CIBSE Guide A Reccomendations (CIBSE, 2012).

The ammendments of rotating the buildings and openings towards the wind direction as well as the change to the openings itself and clerestorey give sufficent stack and Cross-Ventilation, while achieving comfortable indoor temperatures.

Cool Air Intake not as effective with Left Side-Hung Windows as air flow is movement restricted.

WIndow Openings all achieve a velocity of 0.65m/s on the South Facade. Openings could be made bigger in order to allow more ventilation to flow through the space easier and more effectivly.

Indoor temperatures escape through the North of the building causing temperature to drop at a significant rate.

Air flow increases buoyency driven hot air to exhaust out of the higher clerestory opening - Strong connection from the ventilation input up towards the clerestorey window for hot air dispurse at a velocity of 0.66 m/s above the below occupied spaces

Opeining in the roof facing North-East enhances stagnant air to heat up and drive out the roof of the building to disperse at a velocity of 0.6 m/s allowing fresh air flow continuously.

Stale air at a velocity of 0.16 m/s rises towards the top corner of the room however, will not effect the comfort of the space as this area of the room will not be occupied.

Buoyency driven ventilation at a velocity of 0.66 m/s following the ceiling line.

Exhaused air at a velocity of 0.82 m/s - Higher wind velocity above occupied spaces allows the utilisation of stck ventilation.

Window openings velocity of 0.9m/s can drop temperatures in the room and case the thermal comfort inside the room to become uncomfortable.

Y-Axis has a consistancy of 0.16m/s Velocity inside the space casing stagnant air that is slightly uncofortable. Active systems may need to be utilised to achieve indoor comfort when the space is in use.

Uncontrolled Openings allows the air speed to come it at a fast velocity of 0.9m/s. Window Occupied seating may expereicne uncomfort from draft into a wide space of stagnant air

Buoyency Driven hot air becomes stagnant at the top of the space. Moisture caused damp can build up in the space and may require additional openings for upper wind flow to be enhanced maximising passive system potential.

Wind velocity ranging from 1.15 m/s 1.64 m/s enerting the building, can be controlled by the opening of the window.

Cross ventilation accross the main occupied spaces with a wind velocity of 0.49 m/sa noticable but comfortable wind speed according to ‘Table 10.8 - Air Velocities and Thermal Comfort (Wiley, 2015).

Ventilation Intake from direct wind apporach on the 20th July at a velocity up to 1.64 m/s.

This is high but wind speed slows drastically into the more occupied areas of the space.

Cross ventilation Exhausts from the North-East out the opening at a velocity of 0.66 m/s.

Ventilation input from the South-West Facade is at 1.15 m/s. Top hung Windows allow fresh air to access the space easier at a more stable rate. Velocity in the occupied spaces reaches 0.4 m/s - 0.49 m/s - maintaining comfort able wind speeds throughout the space.

Ventilation exhausts at a rate on up to 0.82 m/s towards the North-East which could still offer uncomfortability in the space as the meeting / board room is not a highactivity area (Wiley, 2015).

Air Movement pushed up at a velocity of 0.98 m/s towards the sky light to exhaust the ventilation driven by the narrow for of the space towards the roof.

Sky light in the roof exhausting the hot air inside the room at a velocity up to 1.31 m/s to keep a consistant flow of ventilation in the building.

Stale air exhausts out the North-East Facade through cross-Ventilation strategies

Stagnant Air accross the Z-Axis plane of the Building space causes discomfort within the room in the predominant occupied spaces

Both X and Y axis in the central occupied space of the room cause discomfort with a velocity reading of 0.16 m/s.

Internally heated air has nowhere to dispurse or move due to the nature of the hot air rising to the top of the space and window opennigs are not controlled to enhance wind movement.

Consistant rate of Noticable and comfortable wind speeds around the centralised occupied space alomg the Y-Axis of the room, providing a comfortable and succesful ventilation strategy to the room.

South West Facade incorporates 3 seperated windows that enhance ventilation input into the space all utilising Top Hung Windows for sufficent air flow entrance at a velocity of up to 1.64 m/s.

Noticable and comfortable air of a velocity of 0.4 m/s in accordance with ‘Table 10.8 - Air Velocities and Thermal Comfort’ along both X and Y Axis in the occupied areas.

Intense Solar Glare from the North Window, No solar strategy provided causes unwanted Solar gain to enter the space and apply inconvenient glar making the space uncomfortable in relation to CIBSE Guide A reccomendations (CIBSE, 2012).

Solar strategy to the window would reduce intense LUX levels entering the space at a high LUX ranging from 900 LUX 950 LUX.

278 LUX on the work plane nearest the corner of the room, does not comply with the CIBSE standards and therefore requires ammendments using passive strategies.

Unwanted glare in from of the space causes a uncomfortable level of lux on the work plane.

Minimal level of natural lighting in the psace reaching 90 LUX on the work plane at 700mm. This is too low to comply with CIBSE (Fig. X)and therefore needs ammendments to the space by utilising passive stategys such as larger openings to the space.

Lux Levels reach up to 1564 in the room at the maximum. very uncomfortable levels in accordance with CIBSE Guide A (CIBSE, 2012) reccomendations, requires a solar shading strategy to the window to reduce unwanted solare gain.

Slight discrepency of glare at 750 LUX - 850 LUX. Glare is not ovewhelming to the space. With the window Light Transmission being lowered the glare has drasticall reduced with a decrese of 900 LUX and making the overall space more visually comfortable and allowing light to enter into the deeper plan of the room.

High LUX level at the North of the building due to outside glare and upward facing windows, Transmission is reduced lowering the Glare from 1564 LUX to 701 LUX.

Low level discrepency at a low LUX level of 99 LUX on the work surface which will require active strategy my maximising the potential of solar gain possibly utilising solar cells, the LUX level is not drastic however requires some adjustment to the ammended design.

Sufficent Lux in the occupied space of the centre of the room at a strong LUX level of 404 LUX - Sitting comfortbly in the CIBSE Table (Fig.X).

Good LUX Level of 350 LUX - 450 LUX on the work surface and desks creating a comfortable LUX Level for the users inside the space utilising passive strategies for restricting unwanted solar gain into the space.

High scale comfort levels reach around 350 LUX to 450 LUX throyugh the main occupied spaces in the middle of the room and central work planes causing comfortable levels but reaching the higher margins. Could possibly lead to uncomfortable levels of glare if exposed to a large amound of solar gain.

High comfort levels of LUX on the Workplane of 401 LUX, comfortable space in the corners of the room however possibly change in sun angle can cause more exposure to the space making it uncomfortable for future occupants utilising the space.

Low Levels of LUX ranging between 150 LUX - 250 LUX. In accordance to CIBSE the lux levels are too dark for a board room and making uncomfortable spaces in the room. Passive strategy will need to be incorporated to ammend the low light levels in order to avoid the use of Active systems and artificial lighting in the space.

South Facing windows decline slightly therfore providing sufficent cover from excessive solar gain from the sun.

Very high LUX levels at the North East opening at 1311 LUX causing high levels of uncomfort in the occupied spaces of the board room. The Board Room will be utilised by groups of people possibly using computers and therfore cause high levels of glare and uncomfort during the period of occupnacy.

341 LUX on the central work planes in the board room which is sufficent LUX for the designated space of the board room.

482 LUX in the main occupied psace towards the South - West of the room due to the slanted wall causing a passive strategy of solar protection.

Excessive solar gain with a high concentration of sunlight ranging from 950 LUX and above entering the space causing high levels of glare.

Slight glare at the South of the room at 650 LUX, Does not comply with the CIBSE Guide A reccomendations however the discrepency is not over concerning and allows light to reach deeper into the plan.

LUX Levels cause slight discrepency on one of the work surface at 150 LUX slight use of active systems however, passive systems are still acceptable as there is minimal impact to overall work plane of the room.

Comfortable LUX Levels in the central occupied space ranging between 350 LUX - 500 LUX which complies with the reccomended CIBSE Guide A (CIBSE, 2015).

No Additional or excess solar gain enters the main occupied spaces.

Higher LUX level at the South reaching up to 752 LUX which is not overpoweing to the room however, the high glare allows the deep plan to gain light into the centralised occupied space of the room.

The intensity of the LUX is over the reccomended CIBSE Guide and coused slight glare on the nearby work surfaces howver only by an about of 12 LUX, allowing slight use of acvtive systems.

High Lux of 708 LUX diffused by the maximisation of deep plan both vertically and horizontally when solar gain entrers from the sky light. Light helps utilise the potential for the stack ventilaiton as entering air is heated by the solar gains and drive the hot air to disperse from the sky light. The highe intensity is diffused by the time it reaches the occupied space.

Sufficent LUX as the solar gain is dispersed as it reaches the occupied spaces on the wall due to the limited reflectance on the material on matt concrete.

LUX at a sufficent 466 LUX on the working table at a plane of 700mm800mm above finish floor level.

Adequate LUX levels of around 450 LUX sits comfortably in the CIBSE reccomendations on the work plane providing comfort for the indoor user of the space.

Lower LUX towards the top of the room which is balanced out by the sky light. Not an occupied area therfore will not impact the visual comfort of the internal space and not cause heat from unwanted solar gain.

LUX at 582 - Over the reccomended (CIBSE Guide A, 2012). however, not too drastic. The reccomended LUX is between 300 LUX - 500 LUXhowever eliminating the dark zones by allowing light to enter the spaces that are not predominatly occupied for the majority of the rooms usage.

Glare from the North Side of entering the space but not causing a lotnof visual uncomfort in the space as seen from the perspective of the room, the impact is minimal throughout the space.

Work surfaces result in good sufficent LUX on the work plane of 700mm LUX complying strong ly with the CIBSE Guide Regulations maintaining a LUX of 350 LUX to 450 LUX.