QLI

Functional description

Induction-type displacement flow diffusers provide centrally conditioned primary air (fresh air) to the room and use heat exchangers for cooling and/or heating.

The primary air is discharged through nozzles and induces secondary air (room air), which passes through the heat exchanger.

Primary and secondary air mix and are then supplied to the room, causing only very little turbulence.

QLI–2–G–WVL/1200

QLI–4–U–WHR–KW/1200/WB/P1/VS

Dimensions [mm]

Weights

L_N [mm]

Nominal length

L_WA [dB(A)]

Sound power level

t_Pr [°C]

Primary air temperature

t_WV [C°]

Water flow temperature – cooling/heating

t_R [C°]

Room temperature

t_R [C°]

Room temperature

t_AN [C°]

Secondary air intake temperature

Q_Pr [W]

Thermal output – primary air

Q_tot [W]

Thermal output – total

Q_W [W]

Thermal output – water side, cooling/heating

V_Pr [l/s]

Primary air volume flow rate

V_Pr [m³/h]

Primary air volume flow rate

V_W [l/h]

Water flow rate – cooling/heating

V [l/h]

Volume flow rate

∆t_W [K]

Temperature difference – water

∆p_W [kPa]

Pressure drop, water side

∆p_t [Pa]

Total pressure drop, air side

∆t_Pr = t_Pr - t_R [K]

Difference between primary air temperature and room temperature

∆t_RWV = t_WV - t_R [K]

Difference between water flow temperature and room temperature

∆t_Wm-Ref [K]

Difference between mean water temperature and reference temperature

L_N [mm]

Nominal length

Displacement flow ventilation

The supply air is discharged into the space with a velocity between 0.15 and 0.20 m/s and as close as possible to the floor; the result is a pool of fresh air over the entire floor area. The convection from people and other heat sources causes the fresh air from the pool to rise and create comfortable conditions in the occupied zone. Displacement ventilation is characterised by low airflow velocities and low turbulence. The air quality in the occupied zone is very high. The extract air should ideally be removed near the ceiling.

Heat exchanger

The maximum water-side operating pressure for all heat exchangers is 6 bar.

The maximum water flow temperature (heating circuit) for all heat exchangers is 75 °C; if flexible hoses are used, the water flow temperature should not exceed 55 °C. Units for other pressures and temperatures are available on request.

The water flow temperature (cooling circuit) should be at least 16 °C such that it does not permanently fall below the dew point. For units with a condensate drip tray the water flow temperature may be reduced to 15 °C.

Heat exchanger as 2-pipe system

Air-water systems with a 2-pipe heat exchanger may be used for either heating or cooling. In changeover mode it is possible to use all units within a water circuit exclusively for cooling in summer and exclusively for heating in winter.

Heat exchanger as 4-pipe system

Air-water systems with a 4-pipe heat exchanger may be used for both heating and cooling. Depending on the season, i.e. especially in spring and autumn, it may be possible that an office has to be heated in the morning and cooled in the afternoon.