Carrier AquaForce 30XB series Installation, Operation And Maintenance Instructions

Contents

426.4 - Variable flow evaporatorVariable evaporator flow can be used in standard 30XB chillers.The chillers maintain a constant leaving water temperature underall flow conditions. For this to happen, the minimum flow rate mustbe higher than the minimum flow given in the table of permissibleflow rates and must not vary by more than 10% per minute.If the flow rate changes more rapidly, the system should containa minimum of 6.5 litres of water per kW instead of 3.25 l/kW.6.5 - System minimum water volumeWhichever the system, the water loop minimum capacity is givenby the formula:Capacity = Cap (kW) x N litresApplication NNormal air conditioning 3,25Process type cooling 6,5Where Cap is the nominal system cooling capacity (kW) at thenominal operating conditions of the installation.This volume is necessary for stable operation and accuratetemperature control.It is often necessary to add a buffer water tank to the circuit in orderto achieve the required volume. The tank must itself be internallybaffled in order to ensure proper mixing of the liquid (water orbrine). Refer to the examples below.Connection to a buffer tankBadBadGoodGood6.6 - Maximum system water volumeUnits with hydraulic module incorporate an expansion tank thatlimits the water volume. The table below gives the maximum loopvolume for pure water or ethylene glycol with various systemconcentrations, as well as the static pressures. If the maximumvolume is insufficient, compared to the minimum system waterloop volume, an additional expansion tank must be added to thesystem.30XB & XBP Sizes 250 to 450 500Static pressure bar 1 2 2,5 1 2 2,5Pure water l 2400 1600 1200 3960 2640 198010% EG l 1800 1200 900 2940 1960 147020% EG l 1320 880 660 2100 1400 105030% EG l 1080 720 540 1740 1160 87040% EG l 900 600 450 1500 1000 750EG : Ethylene Glycol6.7 - Evaporator water flow rate30XB & 30XBP Minimum flow rate (1) (l/s) Maximum flow rate (2) (l/s)250 3,6 37,5300 4,0 40,5350 4,3 40,5400 5,3 34,1450 6,0 36,9500 6,7 42,0600 8,1 45,0700 8,9 56,1750 9,6 59,1800 10,4 67,1850 11,0 67,1900 11,8 73,91000 13,1 83,91100 15,1 87,81200 16,4 126,51300 17,5 92,91400 16,4 132,11500 18,8 107,41550 19,9 109,41700 22,0 107,4(1) Minimum flow rate for maximum allowable water temperature difference conditions(10K) under Eurovent conditions(2) Maximum flow rate for a pressure drop of 100 kPa in the exchanger”6 - APPLICATION DATA