Check of Density Limit
The room in which the air conditioner is to be installed requires a design that in the event of refrigerant gas leaking out, its density will not exceed a set limit.
The refrigerant (R410A), which is used in the air condi- tioner, is safe, without the toxicity or combustibility of ammonia, and is not restricted by laws imposed to pro- tect the ozone layer. However, since it contains more than air, it poses the risk of suffocation if its density should rise excessively. Suffocation from leakage of refrigerant is almost
Most importantly, the multi air conditioner system is able to replenish a large amount of refrigerant com- pared to conventional individual air conditioners. If a single unit of the multi air conditioner system is to be installed in a small room, select a suitable model and installation procedure so that if the refrigerant acci- dentally leaks out, its density does not reach the limit (and in the event of an emergency, measures can be made before injury can occur).
In a room where the density may exceed the limit, create an opening with adjacent rooms, or install mechanical ventilation combined with a gas leak detection device. The density is as given below.
Total amount of refrigerant (kg)
Min. volume of the indoor unit installed room (m3)
≤Density limit (kg/m3)
The density limit of refrigerant which is used in multi air con- ditioners is 0.3 kg/m3 (ISO 5149).
NOTE
1.If there are 2 or more refrigerating systems in a sin- gle refrigerating device, the amount of refrigerant should be as charged in each independent device.
For the amount of charge in this example:
Outdoor unit
e.g., charged |
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amount (10 kg) |
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Indoor unit |
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Room A Room B Room C Room D Room E Room F
The possible amount of leaked refrigerant gas in rooms A, B and C is 10 kg.
The possible amount of leaked refrigerant gas in rooms D, E and F is 15 kg.
2.The standards for minimum room volume are as follows.
(1) No partition (shaded portion)
(2)When there is an effective opening with the adja- cent room for ventilation of leaking refrigerant gas (opening without a door, or an opening 0.15% or larger than the respective floor spaces at the top or bottom of the door).
Outdoor unit
Refrigerant tubing
Indoor unit |
(3)If an indoor unit is installed in each partitioned room and the refrigerant tubing is interconnected, the smallest room of course becomes the object. But when mechanical ventilation is installed inter- locked with a gas leakage detector in the smallest room where the density limit is exceeded, the vol- ume of the next smallest room becomes the object.
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room |
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Small | Medium | Large room |
room | room |
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Mechanical ventilation device – Gas leak detector
3.The minimum indoor floor space compared with the amount of refrigerant is roughly as follows: (When the ceiling is 2.7 m high)
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m2 35 | Range below the |
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density limit |
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space | 25 | not needed) |
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floor |
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indoor | 10 |
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Min. | 5 |
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0 |
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Total amount of refrigerant
3
