Utilities Infrastructure Cooling Production 316. Purpose of Today s Presentation. Agenda. GLHN Architects & Engineers, Inc.

Transcription

1 Utilities Infrastructure Cooling Production 316 APPA Institute for Facilities Management Fort Worth January 2019 Bill Nelson PE 1 Purpose of Today s Presentation To provide a broad understanding of central cooling systems (This is a core course - you may see some duplication in other classes) To share information about current refrigerant technologies related to central plants 2 Agenda Introduction Community energy Advantages of a central energy system Efficiencies Chilled Water System Chillers Cooling towers 3

2 Community Energy Labs Library Classrooms Central Energy System Hospital Dormitories 4 Heating and Cooling Systems Advantages Integrated solutions Less equipment Lower service cost Better space utilization Alternate technological option 5 Central Energy System Advantages (cont) Aesthetic options Lower operating cost Better management and energy control Higher overall efficiency Multiple fuel capabilities 6

3 Fundamentals: Water--Ideal Heat Transfer Fluid 75ºF 76ºF Specific Heat 32ºF 1 BTU/lb 212ºF Heat of Fusion 144 BTU/lb Heat of Vaporization 970 BTU/lb 7 Chilled Water System Components Chillers Cooling Towers / Condensers Pumps / Piping IT IS ALL ABOUT MOVING BTU S 8 Chilled Water System Cooling Tower Air Handler Chillers Pumps & Piping 9

4 Refrigerants Halocarbon Methane Series R-11 R-12 R-22 Ethane Series R-113 R-123 R-134a Azeotropic Blends R-500 Inorganic R-717 (ammonia) R-744 (carbon dioxide) Hydro Carbon R-290 (propane) 10 Refrigerant Families CFC = Chlorofluorocarbon Includes R-11, R-12, R-500,113. Widely used. Contain chlorine, fluorine, and carbon. HCFC = Hydrochlorofluorocarbon Includes R-22, R-123. Same general chemical composition, but adds hydrogen atoms. Less environmental impact. HFC = Hydrofluorocarbon Includes R-134a, 410A,407C. Does not contain chlorine. Does not destroy ozone but does add to greenhouse effect. 11 Ozone Depletion Potential (ODP) 12

5 Global Warming Potential () 13 Refrigerant Management Issues Increasing cost of refrigerants Global warming vs. ozone depletion Alternative refrigerants 14 Problem Refrigerant Management The United States is committed to the orderly phaseout of Ozone Depleting Chemicals (ODC s) by the Montreal Protocol (1987), plus the subsequent changes agreed to in London (1990), in Copenhagen (1992) and in Vienna (1995). Montreal (1997), Beijing (1999), Montreal (2007) 15

6 Ionosphere Stratosphere Troposphere Ozone Greenhouse Gases: CFC s, Methane, Carbon Dioxide, Nitrous Oxide UV backscatter and absorption 16 C1 C1 Chloroflourocarbon Molecules UV radiation breaks Chlorine from the Chloroflourocarbon C1 Ozone Molecules Free Chlorine breaks-up Ozone. An Oxygen molecule and a molecule of Chlorine Monoxide are formed. C1 A free Oxygen atom steals Oxygen from the Chlorine Monoxide to form an Oxygen molecule. C1 The Chlorine molecule is now free to destroy more Ozone. 17 OZONE DEPLETION GLOBAL WARMING 18

7 The Perfect Refrigerant High latent heat value Nontoxic Nonflammable Non-corrosive to common materials Environmentally acceptable Low moisture solubility Lubricant soluble Chemically stable High dielectric strength Easily handled and transported Recyclable Detectable at low concentrations Economical Readily available 19 Options For HVAC Refrigerants Fluorocarbons Natural Refrigerants Ozone Depleters (Montreal Protocol) Non- Ozone Depleters (Kyoto Protocol) Class 1 High ODP CFC s ODP ODP ODP ODP R-11 R-12 R113 R-500 Class 2 Low ODP HCFC s ODP ODP ODP R-22 R-123 Higher R-134a R-410A R-407C -ODP Concerns - Concerns - Flammable Lower R-32 R-152a -Toxicity Concerns -Efficiency Concerns -Cost Concerns Today s Chemicals: No Perfect Refrigerant Propane Butane CO 2 Ammonia The Future Direction Focusing on Emissions and Efficiency is fundamental to doing what s right both for business and the environment. Emissions Energy Efficiency 1. Low ODP (Ozone Depletion Potential) 2. Low (Global Warming Potential) 3. High operating efficiency 4. Short atmospheric life 5. Low leakage rates The Best Environmental Solution

8 Future of HFC s Unknown Developed Countries Production of most CFC equipment ends 1990 Montreal Protocol If left unchecked, by 2050, annual HFC emissions could be equivalent to 20% of annual CO2 emissions under a business-as-usual (BAU) scenario R-12 R-11 CFC s R-22 R-123 HCFC s Atmospheric Life R-134a R-245fa x HFC s HFO s R-410A R-407C R-404A ODP R-1234yf R-1234ze many more Continued use of recycled CFC & HCFC refrigerants Developed Countries CFC production ends (R-11, R-12) Developed Countries Production of R-22 equipment ends Developed Countries No new R-22 for service Developed Countries Production of R-123 equipment ends Developed Countries No new R-123 for service Developing Countries Production of R-123 equipment ends Developing Countries No new R-123 for service Kyoto Protocol Developing Countries CFC production ends (R-11, R-12) Today Developed Countries HFC phase out/phase down? looming? Developing Countries HFC phase out/phase down looming? Understanding the Timeline, Know All Okay for Life of Equipment Next Generation Refrigerants Global Warming Ozone Depletion Future not perfectly clear, but development of 2L class appears key to using low F-Gases AHRI Low- Alternative Refrigerant Evaluation Program Future Refrigerants Bring New Concerns, New Solutions Chillers 4 Types Chilled Water System Components Centrifugal Screw Absorption Reciprocating 24

9 Chilled Water System Components: Chillers Centrifugal Chillers 25 Centrifugal Chillers 26 Chilled Water System Components: Chillers Screw Chillers 27

10 Single Stage Absorption Chillers Chilled Water System Components: Chillers 28 Single Stage Steam-Fired Absorption Unit 29 Two Stage Steam-Fired Absorption Unit 30

11 This image cannot currently be displayed. Chilled Water System Components Cooling Towers Forced Draft Induced Draft Condensers Water Cooled Air Cooled 31 Sample Calculations Cooling Tower Grains of Moisture Per Pound of Dry Air Dewpoint or 7 Saturation Temp. F Dry-Bulb temp. F % 60% 40% 20% % 70% 26 50% 30% % Sample Calculations Cooling Tower 200 Ton Tower Cool 600 gpm from 90 o F to 80 o F with a 70 o F wb ambient. BTUH w = 600 gpm x 8.33 LB/gal x 60 min/hr x (90-80)DT = 3,000,000 BTUH 33

12 What Makes a Cooling Tower Work? FILL APPROACH WET BULB RANGE AIR FLOW L/G RATIO TRANSFER UNITS One Drop Cooling Tower FILM DRY BULB TEMP Ta < T <T ENTHALPY ha < h <h HUMIDITY RATIO Wa < W <W BULK H2O AT TEMP T TOTAL HEAT BULK AIR AT TEMP Ta TOTAL HEAT dqw = LCpdt= Kl(adV)(T-T ) SENSIBLE dqs= Kg(adV)(T -Ta) SENSIBLE MASS MASS dm= K (adv)(w -Wa) Induced Draft Crossflow (Double Air Entry)

13 Types of Cooling Towers Hyperbolic Tower Selection Considerations General Considerations Cooling duty Economics Required services Environmental conditions Aesthetics University of Arizona

14 Thermal Storage Integrated Solution Chilled Water or ICE The multi-stage compressor design provides high efficiency and stable operation during both ICE generation and standard cooling. Dual Duty, Single Chiller, Energy Optimization Thermal Storage Integrated Solution Chilled Water or ICE Shifting system load demand Stability of cooling capacity Dual-duty operation Managing energy costs Reduction in demand charges Ice Storage Integrated Solution Case Study The University of Arizona Savings $425 K per year Saved $450 K in Capital costs CASE-SLX138-EN CASE-SLX153-EN

15 Questions? 43