Air Conditioning for Brennan/Mungo MacCallum Complex

Introduction

Levels 3 through 8 of the Brennan and Mungo MacCallum building complex have been provided with 'climate tempering' air conditioning. Under most of the expected climatic conditions, the system will be able to provide comfort. Under extreme conditions, the system will be able to lessen the impact of the adverse conditions. Most rooms have an individual air treatment unit and a control panel on the wall near the light switch.

Control Panel

The control panel on the wall has four buttons, some indicators and a display. The display will show the current temperature in the room. Pressing the TEMP up or down buttons will show the desired (setpoint) temperature, with successive button presses changing the setpoint temperature. The temperature range is 18 - 27°C, but the control system is designed to maintain temperatures within 22 - 24°C. The recommended setting is 22°C.

The FAN buttons cycle through five possible settings:- Off, Automatic, Low, Medium and High. It is recommended that you select Auto as the control system will vary the fan speed to suit the current conditions.

Details of the Building Management Control System

The building is divided into 4 zones:- North East, North West, South East and South West (see sketch below). Within each zone all floors (3 to 8) are supplied from the same equipment.

The equipment for each zone of the building will only allow an individual zone to be heated or cooled, but not both. The decision to heat or cool a zone is made on a calculation of the number of rooms occupied, and whether the majority of the active individual room control panels are asking for heating or cooling. In addition, the outside air temperature is also measured, and if it is near the set temperature, no cooling or heating will be provided (on the assumption that you can open the window)

The control system for an individual room uses a number of factors to decide whether to heat or cool your room:-

  • Your room must have been occupied in the last 20 minutes.
  • If your setpoint is same as the outside air temperature: no heating or cooling.
  • If your zone is in heat mode, but your setpoint requires cooling: no heating or cooling.
  • If your zone is in cool mode, but your setpoint requires heating: no heating or cooling.
  • If your zone is in cool mode, and your setpoint requires cooling: cool.
  • If your zone is in heat mode, and your setpoint requires heating: heat.

Setting a very low (or high) setpoint to try and get faster cooling (or heating) will make no difference, and if set substantially outside the normal working range of 22 - 24°C may result in no air conditioning at all.

The system is based on heat pump technology, and transfers energy from the plant to the rooms by pumping hot or cold water to the fan coil units in the room. The system is designed to be as energy efficient as possible and if you are the only occupant in the building, the system will scale down its energy demand to the actual requirement for your room.

It should also be noted that the capacity of the air treatmnent unit in each room is designed to achieve comfort conditions within ten to fifteen minutes of start-up under average conditions, but can take up to 30 minutes under severe adverse climatic conditions. You can help by actively managing your room:-

  • Prevent early morning overheating by closing the blinds the night before.
  • Prevent winter heat losses by closing the blinds overnight.
  • Open the window to circulate temperate air when possible, and keep it closed when the air is not within the comfort range (too hot, too cold).
  • Sometimes opening the office door open could increase the speed with which hot air can be displaced from the room.