Cooling Tower Designs

Transcription

1 2014 Service Technician Training Program Cooling Tower Designs Daniel S. Krack, CWT 2 Cooling Towers 1

2 Water Cooled Systems More Efficient than Air Cooled % Higher COP than Air Cooled Lower Condensing Temperature than Air Cooled What is a Cooling Tower? Definition of a Cooling Tower Types of Equipment Crossflow Counterflow What is a Cooling Tower? It is an enclosed, steady flow device for cooling water by evaporation through direct contact with air; used in water cooled refrigeration, air conditioning, and industrial process systems 2

3 How does a Cooling Tower Work? Water Surface area is increased Water Evaporates removing heat Air (typically a fan)cools the water via convection How does a Cooling Tower Work? Water Surface area is increased 3

4 Cooling Tower Hot Water Basin Tower Fill How does a Cooling Tower Work Water Evaporates removing heat 4

5 Evaporation How does a Cooling Tower Work? Air cools the water via a fan Tower Fan 15 5

6 Why use Cooling Towers?? So I can sell Chemical? NO! 6

7 It is cheaper than a chiller or a/c system Global Leadership Centrifugal Equipment Chiller Cost Comparison* Cooling Tower First Cost... First Cost... $300/ton $50/ton * 1997 Means Mechanical Cost Data Global Leadership Effect of Condenser Water Temperature on Chiller Energy Temp. Energy Savings 85 F kw/ton Base 83 F kw/ton 5% 80 F kw/ton 8% 75 F kw/ton 15% 70 F kw/ton 21% 65 F kw/ton 26% 7

8 Cooling & Heating (Electricity & Fuel) 30% 60% Chemicals Misc. 5% Water 4% 1% Lighting (Electricity) Typical Utility Budget Typical Air Conditioning System (Evaporative System) (Closed System) 23 Cooling Towers 24 8

9 25 Plate and Frame Dirty Cooling Tower water has to flow between these small channels on the Plate and Frame. Have you seen the water that comes out of a Cooling Tower? Lets take a look at the next slide to show what this nice and clean plate pack will look like in a couple of months! 9

10 COOLING TOWER SYSTEMS MATERIALS OF CONSTRUCTION STEEL GALVANIZED STEEL STAINLESS WOOD FIBERGLASS PLASTIC CONCRETE COPPER(CHILLERS) COOLING TOWER SYSTEMS MATERIALS OF CONSTRUCTION STEEL GALVANIZED CONCERNS: PASSIVATION TO PREVENT WHITE RUST 10

11 COOLING TOWER SYSTEMS MATERIALS OF CONSTRUCTION STEEL STAINLESS(302,304,316) CONCERNS: Chloride attack no muratic acid, no salt bypass from water softener no sea water spray Stainless Steel 11

12 COOLING TOWER SYSTEMS MATERIALS OF CONSTRUCTION WOOD Concerns: Fungi attack Delignification due to oxidizing biocide Wood Tower With a Problem COOLING TOWER SYSTEMS MATERIALS OF CONSTRUCTION FIBERGLASS/PLASTIC Fiberglass-reinforced plastic(frp) side panels, louvers, fan blades PVC is used for fill Polyethylene can be used for hot and cold basins Concerns: Basins susceptible to freezing! 12

13 Cooling Tower with Plastic Components COOLING TOWER SYSTEMS MATERIALS OF CONSTRUCTION Concrete Basin or panels Concerns: Basin can get a lot of dirt in them and require regular cleaning 13

14 COOLING TOWER SYSTEMS MATERIALS OF CONSTRUCTION Copper (Chillers) Concern: Corrosion Scaling Copper Chiller Bundle with Corrosion Typical erosion /corrosion damage seen on tube sheet surfaces Typical look of Belzona protected tube sheet after 5 years 14

15 Main 2 Cooling Tower Designs Cross Flow Counter Flow Main 2 Cooling Tower Designs Cross Flow Water goes down Air goes sideways through the water Cross Flow Tower Configuration 15

16 Cross Flow Mechanical Draft Tower Typical Crossflow Units Conventional Crossflow Cooling Tower Installation 16

17 Main 2 Cooling Tower Designs Counter Flow Water goes down Air goes up through the water Counter Flow Forced Draft Tower Cooling Tower Configurations Counter Flow Principal of Operation 17

18 Forced Draft Counterflow TYPES OF COOLING TOWERS SYSTEMS DIRECT-CONTACT OR OPEN EVAPORATIVE COOLING TOWER INDIRECT-CONTACT OR CLOSED-CIRCUIT EVAPORATIVE COOLING TOWER Direct Contact or Open Cooling Tower Systems 18

19 Vertical Spray Tower Open Recirculating System Spray Pond Industrial Spray Pond 58 19

20 Open Cooling Tower Chiller Cooling Tower Condenser Water Circuit C o n d e n s e r E v a p o r a t o r Chilled Water Circuit Heat Load (Building) Open Cooling Water System Heat (BTU s) Removed by Evaporation Air Flow Air Flow Makeup Bleed Off Heat Exchanger Source: Jim Lukanich 60 OPEN EVAPORATIVE COOLING TOWER 20

21 Once-Through Cooling Water Heat Exchanger Source Water Source: Jim Lukanich Return to Source or Waste 63 Hyperbolic Tower 21

22 Energy Energy Cost Cost Closed Circuit Cooling Tower Chiller Closed Circuit Cooling Tower Condenser Water Circuit C o n d e n s e r E v a p o r a t o r Chilled Water Circuit Heat Load (Building) INDIRECT CONTACT OR CLOSED CIRCUIT EVAPORTATIVE COOLING TOWER 22

23 Closed Recirculating Cool Air Out Warm Air In Air Flow Warm Water 55⁰ F Evaporator Chilled Water 45⁰ F Source: Jim Lukanich 68 Closed Circuit Cooling Tower Closed Heat Rejection Unit 70 23

24 Ammonia Refrigeration Systems Evaporative Condenser 71 Evaporative condenser Open Recirculating System BTU s removed by evaporation Evaporated refrigerant in (ammonia) Air flow Condenser tubes Condensed refrigerant out Sump Building Evaporative Cooling Tower 73 24

25 Forced Mechanical Draft Tower 74 25

26 COOLING TOWERS Questions??? 1/20/14 26