Dimensions

Sensors:

For a list of ALL BLT sensors, click HERE.

Temperature is a measure of the average kinetic energy of molecules in a substance; e.g., air. Temperature is measured, in degrees Celcius, at many locations inthe ITLL. Thermal gradients through the walls, thermal performance of the window glazing, the air stratification and the operations of the air handling unit, the VAV unit, etc. are monitored through temperature measurements. Atmospheric air temperature is measured at the outside weather station, described below.

Flow

Flow is the measure of the continous change of the position of particles in a fluid. It is measured as volume per unit time; e.g., m³/sec. At the ITLL, air flow is measured in the VAV unit and the air handling unit to help control the volume of air in the building. Water and steam flow are measured in the air handling unit, the heat exchanger and the cooling tower. These flows are controlled to maintain a specific temperature in the heating and cooling coils.

Pressure is a measure of a force exerted on a unit area. Pressure is measured in Pascal (Pa), where 1 Pascal equals a force of 1 Newton (N) exterted on an area of 1 square meter. A pressure control unit in the ITLL controls the dampers in the air handling unit to maintain a predetermined air pressure in the building. Water and steam pressure are measured in the water and steam circulation system (the heat exchanger) across the pumps.

Energy is a measure of the capacity to perform work. Energy is measured in Joules (J) where 1 Joule is defined as the work required to move a point where a force of 1 Newton is applied over a distance of 1 meter in the direction of the force. Electrical energy is measured as power applied during a unit time; e.g., kw-hour. At the ITLL, total energy usage of the centrifugal fans in the air handling unit, the pumps in the water and steam circulation system, the condenser water pump in the coolong tower, etc. are measured.

Power

Power is a measure of the amount of energy consumed in unit time. Power is measured in watts (W), where 1 watt is the amount of power required to generate 1 Joule of energy per second. The power usage of the supply and the return fan in the air handling unit is measured in the ITLL.

Mass

Mass is a measure of inertia; i.e., the resistance to change in motion. Alternatively, mass can be defined as a state (manifestation) of energy (E=MC²). Mass is measured in kilograms (kg) or multiples thereof. The kilogram standard is a cylinder of platinum-iridium alloy kept by the International Bureau of Weights and Measures in Sèvres, France. The kilogram is the only base unit still defined by an artifact. At the ITLL, the total mass of condensate pumped by the condensate pump is measured in the water and steam circulation system.

Volume is a measure of three-dimensional space. It is measured in cubic length units. The average, minimum and maximum air volume in the variable air volume unit is measured in the ITLL. These measurements help maintain a set volume of air in the building space.

Direction Sensors

Direction is a measure of the coordinates in order to determine position or attitude. The weather station, located on the roof of the ITLL, determines the direction of the wind.

Speed

Speed is the measure of the distance travelled in unit time. The ITLL weather station measures the average and the maximum speed of the wind.

Concentration is the amount of a substance relative to the total amount of material in a volume. Concentration is most commonly expressed as mass/volume; e.g., grams per liter. When the mass of the volume is used instead, concentration is expressed as mass/mass; e.g., ppm (parts per million). Concentration of dissolved solids in the fluid cooler sump water is measured in the cooling tower.

Insolation is a measure of the amount of solar radiation striking a surface. Maximum insolation, about 1000 watts per square meter, occurs on the earth's surface when the sun is directly overhead.

Various measurements taken in the ITLL; e.g., switch status, relative humidity or valve positions have no units. Hence, these measures are dimensionless.