March_1966 — Page 57

These expansion joints allow for both axial and radial movement 2 in.

Air-Conditioning

up to

The physical arrangement, size, and diversified use of the Ocean Terminal set some very interesting design parameters for air-condition- ing. The following sets out just a few of the required considerations.

1. The Ocean Terminal is physical-

ly comparable to an 83 storey building that is 150 ft. wide, 30 ft. deep, oriented with the 30 ft. side east and west, and lying down.

2. An unknown number of shops of an infinite variety of sizes and shapes.

3. A number of sub-basements and ancilliary areas for various pur- poses all to be air-condition- ed.

4. A variety of internal area usages from cozy coutieres to Chinese seafood restaurants.

5. Large passenger areas where the internal occupancy will vary in- finitely from опе or two to hundreds in a matter of minutes. 6. A requirement that the shop keepers be able to control individually their temperature but never shut off the air-condi- tioning.

7. That certain areas be cooled while other areas be heated simultaneously and at any time. 8. The operating period be 365 days a year and 18 to 20 hours a day.

9. That the total plant capacity be variable from a few tons of refrigeration to full capacity at maximum intermediate efficien- cies.

10. Very limited vertical shafts available and only one horizontal shaft on each side of the struc- ture.

11. Vertical drawings almost impos- sible, except at stair towers. With the above conditions set down as a guide, a process of elimina- tion began which simplified the final choice of systems available. Al- though every low air velocity system was eventually used in one area another, the following systems were eliminated as a basic design concept for the project as a whole:

1. Single duct

по individual temperature control, no simul- taneous heating and cooling.

по individual

2. Multi-zone

temperature control.

T

or

3. Fan coil units high cost, no way to drain, necessity for se- parate arcade air-conditioning.

4. Induction circulator

very

high capital cost, very high operating cost, the necessity for individual drainage.

This left the double duct system as the only design concept for the shops. Multizone, single duct, and fan coil unit systems were used where applicable in other areas. double duct system distributes both

The

Far East Architect & Builder March, 1966

the

cold and warm air through the arcades all year around and individu- ai thermostats in each shop blend the two air supplies to maintain the de- sired condition in the tenant space.

In order to fit ducts into limited space

available above false ceilings, the two air-conditioned levels were divided into 30 approximately equal areas and each area served by a fan room. Each fan room con- recirculated air and a fresh air unit tains a main air-handling unit for the

to precondition the fresh air.

As the physical length of the building, over 1,000 ft., would cause very high pumping horsepowers with normal design temperature limits, we extended the chilled water tempera- ture differential to 15 degrees. This

BA

increase in differential almost halves the pumping requirements.

As such a large differential is dif- ficult to achieve in single air handling units. we use the same water twice. The first time through the main unit to pick up approxim- ately 8 degrees F. and then the second time through the fresh air handling unit where another 7 de- gress F. is picked up.

The warm air is generated by a heating coil in the air handling unit which uses hot condensing water from the refrigeration plant.

This way the warm air is generated at no extra cost for fuel or electric power and an economic heat balance is ob- tained. The rest of the heat of con- densation is removed in a heat ex- changer utilizing the sea water pump- ed through the sea water facility.

The whole air-conditioning plant

be controlled from

a central main control room. This control facility is so designed that any "out of control" aspect will be indicated as an alarm. All fan rooms may be started and stopped, and all major systems stopped from the main con- trol room.

can

No major system can be started from this control panel and no tem- peratures are recorded except those which are useful to know accurately over a long period. This way a pro- gramme can be instituted which forces the operator to visit all parts of the facility at least once a shift.

This same control console is the master panel for all other facilities in the building and read-out is pos- sible on the power supply, sea water pumping, sanitation pumps, fire sys-

tem

condition, lifts, and all mechanical-electrical equipment. A viewing platform has been built so that this control panel is always on view and visitors are welcome.

The total plant capacity of the plant room on the roof is 1,200 tons

a

Substation L.T. switchboard

of refrigeration developed by two centrifugal units driven by 700HP 11.000 Volt motors. The control room and viewing platform mention- ed above are adjacent to the plant

room.

Electrical

The electrical installation is divid- ed into the following parts:

1. High tension supply and distri-

bution.

2.

Low tension supply and distribu- tion.

3.

Public lighting.

4. Mechanical equipment drive and

control.

5. Communications.

High tension power is fed into the building through two 11,000 Volt feeders in parallel with the China Light & Power Co.'s main. This H.T. is distributed to four 1500 KVA transformers and to the 11,000 Volt starting gear for the refrigeration machinery drives.

The low tension power from the transformers is fed into two divided substations from which L.T. is dis- tributed to sub distribution boards on

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