MITSUBISHI ELECTRIC / KEY TECHNOLOGIES
Inverter-driven compressor technology All CITY MULTI compressors are of the inverter-driven type, capable of precisely matching a building’s cooling and heating demands. The compressor varies its speed to match the indoor cooling or heating demand and therefore only consumes the energy that is required. When an inverter driven system is operating at partial load, the energy efficiency of the system is significantly higher than that of a standard fixed speed, non-inverter system. The fixed speed system can only operate at 100%, however, partial load conditions prevail for the majority of the time. Therefore, fixed speed systems cannot match the annual efficiencies of inverter driven systems. Using proven single inverter driven compressor technology, the CITY MULTI range is favored by the industry for low starting currents (just 8 amps for a 20HP outdoor unit) and smooth transition across the range of compressor frequencies.
Heat recovery system
HEATING / COOLING CAPACITY
Heating / Cooling Capacity
Comparison between different systems with different pipe connection points
100% 2 pipes
Linear Capacity Control
CITY MULTI R2
Total connections
20
Outdoor unit
Drastically reduces the amount of piping
BC controller
15%
compressor Indoor units
Low
Compressor Frequency
=Piping connections
High 3 pipes
Total connections
58
Outdoor unit
STABLE AND SMOOTH OPERATION
Indoor units IMMAGINE IN BASSA
IMMAGINE IN BASSA
Solenoid box
Solenoid box
=Piping connections
Capacity 100%
100%
100%
3-inverter compressors
2-inverter compressors
1-inverter compressor
No.3
How does the R2 / WR2 heat recovery system work with two pipes?
No.2
The secret of the VRF CITY MULTI heat recovery system lies in the BC controller. The BC controller contains a liquid/gas separator which allows the outdoor unit to produce a two-phase mixture of hot gas for heating and liquid for cooling delivered through the same pipe. Three pipe systems use one pipe for each
No.2 No.2 15%
Solenoid box
IMMAGINE IN BASSA
Capacity
Capacity
Solenoid box
Inverter
7.5% Load
No.1
5%
No.1 Load
No.1
No.1
No.1
Load
of these two phases. The mixture is separated when it reaches the BC controller, and the correct phase (gas or liquid) is sent to each indoor unit in relation to individual demand for heating or cooling.
CITY MULTI R2
Heating = gas refrigerant Cooling = liquid refrigerant
2 R2/RW2 REFRIGERATION CIRCUIT The two-phase gas-liquid refrigerant from the outdoor unit is split into gaseous refrigerant and liquid refrigerant by the gas-liquid separator in the BC controller. BC controller
1 The high pressure and low pressure values determine the compressor activation frequency and heat exchanger operating mode, and also control the thermal exchange volume..
The BC controller separates the refrigerant correctly for each indoor unit in relation to operating mode of the unit itself. Refrigerante gas
Refrigerante a due fasi gas-liquido ad alta pressione
Unità esterna
16
Refrigerante liquido
Refrigerante gas
Refrigerante liquido
Unità interna
Riscaldamento
Riscaldamento
25°C
26°C
Raffreddamento Raffreddamento
22°C
3 Refrigerant flow regulation in relation to temperature difference between intake air and delivery air.
24°C
17