Energy Saving Calculation Between Sliding Door and Revolving Door

Environmental Energy Consumption = Temperature difference(T)In/Out ×Air exchange amount(M) ×Air heat capacity(C)* .

* Heat capacity is the measurable physical quantity that characterizes the amount of heat required to change a body’s temperature by a given amount, the measurable physical quantity that characterizes the amount of heat required to change a body’s temperature by a given amount. Here air capacity =1.2Kj/m³ .

▪  Take the city Hong Kong (China) as an example .

Average temperature is about 27℃ .

Inside temperature as human body comfortable level 20℃ .

A common star hotel with 500 rooms, 60%-80% occupancy rate, with 1.5 person in every room, hosting 450-600 guests everyday, whose average daily entry and exit is 4-5 times each, coming with 1800-3000 times entry and exit totally. Considering other factors such as other visitors or food takeout etc., we choose a random value as 4320 .

▪  About the Doors

* Revolving Door with the diameter 3200mm and opening height 2200mm(Total height 2500mm, with canopy height 300mm).

* Sliding Door with the opening width as 1700mm and height as 2200mm .

▪  Calculation for Air exchange amount – Sliding Door

Air Exchange Amount=Open area (A) ×Opening time (S)×Air movement(V)=3.74 x8640 x4.5 = 145,411.2 m³.

Note:

Opening area (A)=1.7×2.2=3.74m².

Opening times (S) =8,640s/day.

Air movement(V) =4.5m/s .

*Assuming 3 persons each time, opening/closing hold time as 10 seconds if be converted to 60% of fully energy, leads to a result as: 4,320/3*10*0.6= 8,640 seconds every day.

*Air flow (v) =4.5m/s (Average wind speed in Hong Kong is about 5.5m/s per year，Considering temperature difference and air-conditioning pressure, modify it to 4.5m/s).

▪  Calculation for Air exchange amount – Revolving Door

Air Exchange Amount= Air volumn (V) ×Revolving circles(N) =17.68448 x2,160 = 38,198.4768 m³.

Note:

Air volumn(V)= Cross-section(A) ×Height(H) =3.14×(3.2/2)²×2.2=17.68448m³.

Revolving times(n)=2,160r/d (rounds/day)

*4320 persons everyday，6 person per rounds，revolving door revolves 2 rounds at high speed 4r/m when there is pedestrian and revolves 1 round at a low speed 2.5r/m when it’s vacant. So 4320/6 x(2+1)=2,160 r/d .

▪  Environmental Energy Consumption

* Sliding Door

Environmental Energy Consumption = Temperature difference(T)In/Out ×Air exchange amount(M) ×Air heat capacity(C) =7 x145,411.2 x1.2 =1,221,454.08 kj .

* Revolving Door

Environmental Energy Consumption = Temperature difference(T)In/Out ×Air exchange amount(M) ×Air heat capacity(C) =7 x38,198.4768 x1.2 =320,867.21 kj .

Note:

Temperature difference(T)In/Out =27-20=7℃ .

Air Heat Capacity =1.2kj/m³.

▪  Conclusion

1,221,454.08 /320,867.21=3.81 .

About the Environmental Energy Consumption between Sliding Door and Revolving Door, the former is over 3 times that of the latter .