Occupants

As was mentioned in section 4.1, human beings give off heat at a metabolic rate which depends on their rate of working. The sensible and latent proportions of the heat liberated for any given activity depend on the value of the ambient dry-bulb temperature: the lower the dry-bulb temperature the larger the proportion of sensible heat dissipated.

Typical values of the sensible and latent liberations of heat are given in Table 7.16.

The figures for eating in a restaurant include the heat given off by the food.

Deciding on the density of occupation is usually a problem for the air conditioning designer. A normal density for an office block is 9 m2 per person, as an average over the whole conditioned floor area. The density of occupation may be as low as 20 m2 per person in executive offices or as high as 6 m2 per person in open office areas.

Some premises may have much higher densities than this; for restaurants, 2 m2 per person is reasonable, but for department stores, at certain times of the year, densities may reach values of 4.3 to 1.7 m2 per person, even after allowance has been made for the space occupied by goods. In concert halls, cinemas and theatres, the seating arrangement provides the necessary information but in dance halls and night clubs estimates are open to conjecture. Occupation may be very dense indeed. A figure of 0.5 m2 per person is suggested tentatively.

Activity

Metabolic

Rate

W

Heat liberated in W

Room dry-bulb temperature (°C)

20°

22°

24°

26°

S

L

S

L

S

L

S

L

Seated at rest

115

90

25

80

35

75

40

65

50

Office work

140

100

40

90

50

80

60

70

70

Standing

150

105

45

95

55

82

68

72

78

Eating in a restaurant

160

110

50

100

60

85

75

75

85

Light work in a factory

235

130

105

115

120

100

135

80

155

Dancing

265

140

125

125

140

105

160

90

175

Posted in Air Conditioning Engineering


Добавить комментарий

Ваш e-mail не будет опубликован. Обязательные поля помечены *