Rotary Heat Exchangers Pty Ltd

Energy & Cost Savings

EXAMPLE OF ONE MYLAR RHE2750 WHEEL FREE HEATING 8,000 L/S FRESH AIR IN A MELBOURNE INDOOR POOL
ASSUMPTIONS
Met. Statistical Data for Melbourne calculated by CSIRO and published by AIRAH.
Taking a typical Aquatic Pool in Melbourne with an indoor average Pool Hall temperature 27 C, using the data analysis from the above reference shows that in order to raise ambient air to 27 C requires a total 128,375 kWh per annum per m3/s air flow. Note for any higher Pool Hall temperature savings would be higher.

ENERGY & COST SAVINGS FOR BALANCED FLOW (EQUAL EXHAUST & FRESH AIR) OF 8,000 l/s USING ONE S426RHE2750   2750mm Dia SERIES 426 HIGH PERFORMANCE MYLAR ROTARY HEAT EXCHANGER

PERFORMANCE      83% Heat Recovery at 173 Pa air flow pressure drop
ESTIMATED ANNUAL ENERGY SAVED
1 kWh  = 3.6 MJ = 3.6 GJ/1000
Energy Saved              =          3.6 x 8 x 128,375 x 0.83                     GJ
                                                            1000                       
                                    =          3,069 GJ
Natural gas required to heat air using a conventional boiler and hot water heat exchanger system assuming a 75% overall efficiency for air heating would require
Natural Gas Savings                           =          3,069/0.75       =          4,092 GJ Natural Gas

ESTIMATED N.G ENERGY COST SAVINGS
For a NG cost of $10/GJ  Annual NG Cost Savings is
                                    =          4,092 x 10
                                    =          $40,920 pa

ELECTRICAL FAN POWER ATTRIBUTED TO RHE FAN USE
 FLOW x PRESSURE DROP/ FAN EFFICIENCY
FRESH AIR SIDE                                         8.000 x 173/0.75         =          1845 We
EXHAUST AIR SIDE                                   8.000 x 173/0.75         =          1845 We
TOTAL parasitic power loss                                                   =          3.69 kWe 
Assuming 8,000 h/a  operation total fan energy used             =          29,520 kWh
Assuming a 20c/kWh cost of electricity                                 =          29,520 x 0.20  = $5,904 pa
Thus reducing savings to $40,920 – $5,904                           =          $35,016 pa
This results in a less than 1 year payback on the cost of the Rotary Heat Exchanger excluding installation costs.
Maintenance costs for the Mylar wheel is very low and they have a proven long life in aquatic environments.

The $ savings will double to $70,000 per annum, if gas cost rises to $20 per GJ resulting in a less than 6 months payback. Todays domestic prices in Victoria exceed this gas price.

ANNUAL GREENHOUSE GAS EMISSIONS REDUCTION
Ref: Australian Govt Department of Climate Change
For Vic NG  GGE is 57.3 kg CO2-e/GJ Resulting in  4,092 x 57.3/1000       =  234.5 t CO2-e emission reduction per annum.

For Vic Electricity GGE is 1.31 kg CO2-e/kWhe Resulting in 1.31  x  29,520/1000   =          38.7t CO2-e emission increase per annum.

NET REDUCTION IN GGE
            =          234.5   -           38.7     =          195.8  t CO2-e emission reduction per annum.


image-79149-src-Dsc00312RHEb.jpg
UNIQUE AUSTRALIAN MYLAR WHEELS
LESS THAN 12 MONTHS EHERGY SAVINGS PAYBACK ACHIEVABLE
Revised 30 Oct 2014 Copyright © 2014 Bill Ellul. All rights reserved