Multifamily: Typical Measures Mid and High-Rise Multifamily Buildings. Nick Dirr, Association for Energy Affordability

Transcription

1 Multifamily: Typical Measures Mid and High-Rise Multifamily Buildings Nick Dirr, Association for Energy Affordability

2 No part of this document may be reproduced, stored in a retrieval system or transmitted in any form, by any means, including mechanical, electronic, photocopy, recording, or otherwise, without prior written permission of the Association for Energy Affordability, Inc (AEA).

3 Mid and High Rise Building Characteristics Central systems more common Domestic Hot Water (most common) Heating (depends on building stock) Cooling (depends on building stock) Ventilation Common Areas Lobbies, Hallways, Stairwells, Laundry, Community Rooms, Storage

4 Common Central DHW Opportunities

5 DHW Replacement?

6 More Commonly See This

7 Water Heater Replacement Condensing Boilers are sometimes good options Boiler and Separate Tank Integrated Tank High efficiency opportunities because very good chance at incoming water temperatures less than 135 F Tankless wall-mount options more limited in larger MF due to GPM limitations Pay attention to venting limitations! Side-wall not always possible and limited allowable venting lengths Copper-fin-tube boilers lower cost, lower efficiency alternative

8 Old High-Rise with Steam Boilers and Tankless Coils If burning oil limited options If burning natural gas investigate separate DHWonly boiler

9 DHW Temperature Controls Water Temperatures too Hot! Install mixing valves at water heater Repair mixing valves Or just turn-down aquastat (it s a freebie)

10 DHW Recirculation Pumps Intention is to always have hot water available so that water is not wasted Trade-off between fuel use and water use Common MF set-up is to run continuously (8760!)

11 DHW Recirculation Various strategies to conserve both (recirculate water only when necessary): Time clocks (shuts pumps off at night) Aquastats (shuts pumps off based on temperature) Demand Controls (controls DHW temp based on demand). Packaged Pump Controls (Taco, D Mand Circ, turns pump on or off based on flow and temperature).

12 Central Heating Opportunities Heating System Controls System Balancing Fixing Leaks (fix the root cause!) Insulation Burner Replacement (add modulation) Boiler Replacement

13 Central Heating Controls Outdoor Resets for Hydronic (hot water) Systems Cycle-Timer for Steam Systems Advanced Controls Wireless Temperature Sensors in Apartments Remote Access via Internet Distribution Controls TRVs

14 Too hot at night, too cold during day. Why?

15 Remote Monitored Heating Sensors (wireless)

16 Install New Equipment Higher Efficiency (condensing or induced draft) Don t assume the nice-looking brochure efficiency Operations, controls, near-boiler piping, and any pumping is critical to getting your efficiency Modulation (higher turndown better to match loads) Make it right-sized Experience has shown you can reduce existing size by 10-20%, but triple-check your numbers!

17 System Balancing Get heat to all parts of the building at nearly the same time Don t overheat the B-line apartments because H-line apartments are too cold With a balances system you can minimize boiler temperatures or steam pressure and everyone will still be happy Tenant and Operator education

18 Fixing the root cause (not the symptom) Rusted boiler could mean oxidation from lots of fresh city water. But why? Leaking pipes (mains and vents) So just don t replace the boiler! Or leaking and discharging pressure relief valve Check to see if water-logged expansion tank first Don t just install a higher pressure rated relief valve

19 During you want to make sure that you note the water line in this tank. Filled tank will not allow expansion and will cause pressure relief valve to discharge

20 Steam leaks You will be able to see this during heating season only, but during non-heating season you will have to use visual indicators and interview to assess this condition.

21 Use this observation to make qualitative assessment of what is going in the building Indicative of steam and water leaks

22 Heat exchange surface is compromised

23 Not enough elements or damaged fins

24 Pipe Insulation It s not rocket science. But many times owners don t know their buildings, and operators have no incentive to efficiently operate Sometimes 100 s of feet of uninsulated pipes Old asbestos removed but pipe never reinsulated

25 Central Cooling Opportunities (Chilled Water) Scheduling Controls Higher Efficiency Units Variable Speed Pumping Opportunities Compressor and refrigerant optimization

26 Older Air-Cooled Chiller Systems

27 Newer Air-Cooled Chiller Systems

28 Controlling Air Infiltration in Mid and High Rises Managing Stack Effect Balancing Mechanical Ventilation

29 Stack Effect Winter Mode Building Provides Heat Heated Air Rises Increases Pressure at Top Decreases Pressure at Bottom Higher P = Higher Air Flow Exfiltration at Top Infiltration at Bottom 29

30 The Neutral Pressure Plane Where is the least effective place for you to concentrate your time air sealing?

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32 Smoke Louvers At Top of Stairwell FD requires that there be a vent at top of interior stairwells Creates natural stack in building Could install motorized louvers operated by smoke/heat sensors. Must coordinate with fire dept Seal Top of Building

33 Cracks (rooftop machine room) Seal Top of Building Doors & Windows (bulkhead doors, very common) Common Bypasses and Sources of Air Flow

34 Seal Top of Building

35 Holes (bulkhead) Gaps (elevator room)

36 Seal Bottom of Building

37 Seal pipe and wire penetrations Caulk around door frames

38 Seal penetrations from parking garage

39 Weatherstrip and Replace Seal Penetrations from fire hose cabinets Pipe Penetrations (apt steam riser)

40 Seal around garbage chutes

41 Seal around hallway pressurization grille perimeters and garbage chutes

42 Seal Outside Walls and Openings Weatherstrip windows, doors, including balcony/patio doors and seal window trim Exhaust fans and ducting All service penetrations Baseboard heaters Electrical receptacles Baseboards

43 Seal behind baseboard radiators

44 Identifying Air Sealing Opportunities Common Area Windows Window Lintels (airflow into interstitial spaces)

45 AC Sleeves The great tragedy of many Multifamily buildings

46 Compartmentalize Garages Vented mechanical rooms Garbage compactor room Emergency generator room High voltage rooms Shipping docks Elevator rooms Workshops

47 Insulation Target areas: Roof Basement ceilings Walls (in very limited applications) Access a major issue! Garden style apartments Some emerging technologies that make it possible to affix insulation to interior sheetrock wall, but $$

48 Find & Fix Thermal Weaknesses High Rise Insulation in large multifamily buildings is often difficult to inspect Could be sandwiched between layers of masonry, form the base layer for EPS wall systems or under the roof membrane Probing through the covering layer is impossible or ill advised. We must resort to detective work.

49 Is this roof insulated?

50 Lets see Nothing here

51 Insulating a flat roof

52 Central Mechanical Ventilation

53 Central Exhaust System Kitchen or bathroom exhaust fan may serve 1 line or multiple lines via a single vertical shaft

54 Balanced System with Supply To Corridors Intention: Air coming in = air going out

55 What Is Actually Going On Flows are all over the place Systems are completely unbalanced Stack effect takes over As Delta T between indoor and outdoor increases: Top pressurized Bottom depressurized

56 Causes of Imbalance Taped up grilles due to smell transmissions from other apartments, or bugs! Grilles covered by bookcases or other furniture Duct Leakage Dirty grilles

57 Not At All Uncommon

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59 Cleaning of Fan and Fan Housing

60 Two Major Sources of Duct Leakage 1. Termination point between horizontal runout of exhaust riser and sheetrock wall 2. Point at which the vertical riser meets the roof May represent up to 50% of leakage in duct system

61 Manual balancing dampers: Problems: Typically found Adjusting one register in a system impacts the airflow through other registers Pressures throughout the year fluctuate due to wind effect and stack effect (may be well balanced for summer, but will not perform in winter)

62 Constant Air Regulators (CAR Dampers)

63 Electrical Lighting Appliances Fans Pumps Elevators

64 Lighting in Mid and High Rise MF In-Unit Lighting not much different than low-rise MF Hardwired fluorescent in kitchen and bathroom Often responsibility of owners But still similar mix of lighting as SF and low-rise MF (some incandescents, some CFLs, some hard-wired fluorescent) Burn-times tend to be longer (less rooms and less daylight)

65 Lighting in Mid and High Rise MF Common areas are huge lighting opportunity for Mid and High Rise! Hallways/Corridors Stairwells (some never used) Lobbies All on 24/7 (8760!) Much better payback due to long on-times

66 Common Areas Lighting Opportunities Fixture Replacement/Retrofit Replace Magnetic Ballast T12 Fluorescent with Electronic Ballast T8 Fluorescent (~30% wattage savings) Reduce lighting where over lit (~30-50% wattage savings) Replace Incandescent and CFL exit signs with LED Exit Signs (~50-80% wattage savings) Replace incandescent recessed fixtures and sconces with appropriate CFL (par30 or pin-based) (~60-75% wattage savings)

67 Common Areas Lighting Opportunities Occupancy Sensors Bi-Level lighting in rarely used stairwells and some hallways Dim lights to 50% or more when no one is around, and switch to 100% when motion activated Rarely used storage rooms and common bathrooms Office spaces Laundry Rooms

68 Exterior Lighting Opportunities Replace inefficient lighting Reduce unnecessary over-lighting Improve light quality Install/repair photosensors Install/repair timers

69 Refrigerators Opportunities are similar, but with certain caveats Split incentive owner buys, tenant benefits Don t just measure the refrigerator size, but pay attention to doorway and hallway size (everything was remodeled except the refrigerator) Bulk purchasing and scheduling

70 Fans (Exhaust and Supply) Many existing are belt driven I hear it working, but is it really working? Opportunities for more efficient fans Direct Drive and ECMs Variable speed when appropriate Operating schedule (does the fan need to be 24/7?) Mechanical Rooms Fire/Smoke Suppression

71 Pumping Opportunities Heating and DHW Circulators Right-Sizing Scheduling and Operations Sequencing ECMs City-water boosting systems Variable speed or bladderexpansion tanks

72 Elevators Some elevators are very old and inefficient MG Sets are the dinosaurs Common replacements are AC Variable Speed (VVVF) (best) or SCR systems (being phased out) Expensive and only cost effective if upgrading entire elevator system anyway (use the incremental cost) Hydraulic elevators (usually 5 floors or less) have limited retrofit options, already pretty efficient

73 Laundry Front loading more efficient Often not an easy retrofit, equipment is leased through a third party vendor Recommend incorporating energy efficiency in next lease renewal

74 And many other retrofits (these are just the more common) But remember, physics is physics. If you think in whole building terms and think like water or air or electricity, you can find an appropriate solution to almost any problem. And ask one of your WAP colleagues about those headscratchers. We are all in this together.

75 Thank You for your time! Nick Dirr Association for Energy Affordability