An Approach to Heat Recovery in Rural Alaska Introduction Introduction Background – Maintenance & Repair Background – Maintenance & Repair Small Scale: 50 kW to 3500 kW Small Scale: 50 kW to 3500 kW Heat Recovery: SAVES Fuel - NOT Primary Heat Heat Recovery: SAVES Fuel - NOT Primary Heat Keep it SIMPLE Keep it SIMPLE

Rules of Thumb 1/3 Electricity : 1/3 Jacket Water : 1/3 Exhaust 1/3 Electricity : 1/3 Jacket Water : 1/3 Exhaust 2000 BTU/kW-Hr (jacket water) 2000 BTU/kW-Hr (jacket water) 100,000 BTU delivered Heat = 1 gallon #1 Diesel 100,000 BTU delivered Heat = 1 gallon #1 Diesel 0.3 x Power Plant Annual Fuel Use x x Power Plant Annual Fuel Use x 0.6 Pumping Energy Costs <= 10% Fuel Value Pumping Energy Costs <= 10% Fuel Value Size System Flow for 2/3rds Peak Load Size System Flow for 2/3rds Peak Load

End-Users Water Plant / Washeteria Water Plant / Washeteria Schools Schools Public Facilities (Clinics, City Offices, Rec Centers) Public Facilities (Clinics, City Offices, Rec Centers) Ice / Cold Storage (low temp absorption chiller) Ice / Cold Storage (low temp absorption chiller)

Design Considerations Power Plant Diesels (heat rejection, pump capacity) Power Plant Diesels (heat rejection, pump capacity) –No In-Line Booster Pumps –Secondary Pumped Loop –Power Generation = Primary –Power Generation = Primary End-User Heat Loads End-User Heat Loads –Historical Fuel Use Based –HDD and Composite UA

Design Considerations contd Pumping Pumping –Minimize Pumping Energy (valves/restrictions) –Redundancy Arctic Piping Arctic Piping –Welded steel, HDPE jacketed –Copper where indoors/utilidors Instrumentation Instrumentation –Thermometers (thermo-wells) –Pressure Gauges (isolation valves) –Air Vents (minimize + isolation valves)

Design Considerations – contd Air Control Air Control –Air Eliminator (rol-air-trol vs. air scoop) –Expansion Tank Sizing (40F or –40F) Pre-charge (set for specific application) Pre-charge (set for specific application) Arctic Piping Loop Fluid Arctic Piping Loop Fluid –Ethylene / Propylene / Water –Ethylene / Propylene / Water MAINTAINABILITY / ACCESS MAINTAINABILITY / ACCESS –Equipment Location –Valving

End-User Connections Direct Connection Direct Connection Full Boiler Flow thru Heat Exchanger Full Boiler Flow thru Heat Exchanger –Heat Availability close to Boiler Capacity Partial Boiler Flow thru Heat Exchanger Partial Boiler Flow thru Heat Exchanger –Heat Availability << than Boiler Capacity

Equipment Heat Exchangers Heat Exchangers –P&F Clip on Gaskets (>70 gpm) –Brazed Plate (<70 gpm) Valves Valves –Lug Style Butterfly –Full Port Ball Valves (no gate valves) (no gate valves) Arctic Piping Arctic Piping –Preinsulated Arctic Pipe Package

Daily Operations Daily Log Daily Log –Monitor and Record Temperatures, Pressures, Pump Operation Temperatures, Pressures, Pump Operation –Check Glycol Concentration & Inhibitors

Typical Jacket Water Heat Rejection of Diesels

Typical Jacket Water Heat Rejection of Diesels (continued)

6-Port P&F Heat Exchanger

Wood Boiler & Heat Exchanger

Electric Boiler & Heat Exchanger

Inaccessible Heat Exchanger

AVEC Ambler Plant

AVEC Kiana HRM

AVEC Kiana HRM-radiators

AVEC Anvik Heat Recovery

AVEC Anvik Heat Exchanger

IASD Anvik Heat Recovery Module

IASD Anvik Heat Exchanger

Selawik Power Module

Heat Exchanger & BF-Valve

Secondary Pumped Loop HXR

AMOT Tree

AVEC Selawik HRM-before

AVEC Selawik HRM-New Style