Results 1 to 10 of 10
  1. #1

    New House- New System Design

    I live in Pawling NY and just bought a modular home 4200ft (1400 1st + 1400 2nd + 1400 basement). Currently has no duct work and oil heat.

    It is my intention to design 2x heat pump systems. One for the top floor (1 zone) and 1 for basement and main floor (2 zone). I have been in service for 5 years but this is my first design from scratch so cut me a little slack. I used loadcalc on my tablet and calculated the building envelope and the room by room.

    Please check my assumptions:

    1) System should be sized based on heating need.
    2) 2 Stage units would be better to compensate for the large difference between heating and cooling needs.
    3) Basement will be ceiling supply and return, 1st floor will be floor supply central return, 2nd floor will be ceiling supply/ central return... this is the most economical for installation time... should be ok, right?
    4) The backup heat will be the oil hot water baseboard (how will this work?? will the unit reach max capacity and not be able to keep up so it will call for supplemental heat or does the unit lockout at a certain temperature and the backup heat is on 100% of the time during the bitter days(sorry most of my experience is refrigeration)?

    Thanks in advance for the feedback.

  2. #2
    Join Date
    May 2000
    Location
    Indianapolis, IN, USA
    Posts
    34,601
    1. No, you'll never size for heating load. Remember that an X ton heat pump at 47 is probably a 1/2X at 17 so it would be near impossible to size for heating. Size to cooling and have your backup handle the heating design. Say 2800 sq ft above ground needs 75K heat. Probably needs 1/2 that for cool. To get 75,000 BTU at 17 out would require 2 5 ton units and a 2.5 ton unit.

    2. Most 2 stage units are 75-80% of high when on low. Only the A-S/Trane 20 is closer to 50/100.

    3. Basement is heating needs so low supply & return.

    4. With baseboard backup I'd have the stat shut the pump off when it can't keep up and let the baseboard take over. You could save a bit by letting the heat pump keep going but the output air will be cool and drafty and may not be very comfortable.

  3. #3
    Baldloonie Thanks for the quick response!

    1) According to loadcalc my heat loss for the envelope is 58,260 btu (unfinished basement walls) if I finish the walls it drops to about 42,000 btu (dont have the calculations in front of me)... i know I still need a back up but I was thinking 2x 3t 2stage units would work nicely. It would come out to 25k (stage 1) 36k (stage2) so summer time will be all stage one and stage 2 all winter.

    2) Ok

    3) That would be optimal for heat, I will be having a home theater and office down there also so it will have cooling needs. Basement and main floor will be off the same system so it is most practical to keep the supplies in the ceiling... maybe my fear of designing a complicated duct system is influencing me here. Also the system for the top floor will be ceiling supply/return, will this be inadequate?

    4) I was looking at the Luxaire HL8036f1/f3c which boasts that the it has warm to touch DAT even on the coldest days. The performance data shows 36k at 47 and 24.4k at 17 I was imagining that this is achieved by reducing fan speed during decreased capacity to keep a constant DAT if that is the case I think queuing the additional baseboard heat in conjunction with the hp would be most economical because every btu out of the HP cost much less than out of oil

    http://www.upgnet.com/PdfFileRedirec...ltg-a-0410.pdf
    http://www.joinluxaire.com/products/...2744/HL8B.aspx

  4. #4
    Join Date
    May 2000
    Location
    Indianapolis, IN, USA
    Posts
    34,601
    What's your cooling needs?

    That Lux is 70% on low which is better than most but still 2 of them puts you over 4 tons of cooling (both on) for 2800 sq ft above ground in NY. This ain't Houston!

    You can run low airflow to keep discharge temp up but kills HSPF and hard on the compressor.

  5. #5
    Join Date
    Jan 2004
    Location
    PA
    Posts
    68,777
    First stage usually doesn't have a good SHR, so you will probably have high humidity if you size to the heating load. So you will also need a whole house dehumidifier in the summer.
    Contractor locator map

    How-to-apply-for-Professional

    How many times must one fix something before it is fixed?

  6. #6
    Join Date
    Nov 2004
    Location
    SW FL
    Posts
    6,429
    Quote Originally Posted by dan_liptak View Post
    Baldloonie Thanks for the quick response!

    1) According to loadcalc my heat loss for the envelope is 58,260 btu (unfinished basement walls) if I finish the walls it drops to about 42,000 btu (don’t have the calculations in front of me)... i know I still need a back up but I was thinking 2x

    Basement and main floor will be off the same system so it is most practical to keep the supplies in the ceiling.

    The performance data shows 36k at 47 and 24.4k at 17
    http://www.upgnet.com/PdfFileRedirec...ltg-a-0410.pdf
    http://www.joinluxaire.com/products/...2744/HL8B.aspx
    42,000 BTU/HR was calculated using what Winter design temperature?
    Designer Dan
    It's Not Rocket Science, But It is SCIENCE with "Some Art". ___ ___ K EEP I T S IMPLE & S INCERE

    Define the Building Envelope and Perform a Detailed Load Calc: It's ALL About Windows and Make-up Air Requirements. Know Your Equipment Capabilities

  7. #7
    Join Date
    Nov 2004
    Location
    SW FL
    Posts
    6,429

    Thumbs up BALANCE POINT CHART indicates 15'F

    Quote Originally Posted by dan_liptak View Post
    Baldloonie Thanks for the quick response!

    1) According to loadcalc my heat loss for the envelope is 58,260 btu (unfinished basement walls) if I finish the walls it drops to about 42,000 btu

    .. i know I still need a back up but I was thinking 2x


    4) I was looking at the Luxaire HL8036f1/f3c which boasts that the it has warm to touch DAT even on the coldest days.

    http://www.upgnet.com/PdfFileRedirec...ltg-a-0410.pdf
    http://www.joinluxaire.com/products/...2744/HL8B.aspx
    Using two LUXIARE 2-ton HEAT PUMPS would have a very low Balance Point _ _ 15'F _ _,
    IF THE Heat Loss is actually ~ 42,000 BTU/HR at 5'F.

    VERY LOW BALANCE POINT OBVIOUSLY indicates advantageous systems that are much more Economical
    than the use of OIL.

    Use of 2-ton units would also seem to provide GOOD Comfort levels in the Summer.

    ATTACHMENT
    Attached Images Attached Images
    Designer Dan
    It's Not Rocket Science, But It is SCIENCE with "Some Art". ___ ___ K EEP I T S IMPLE & S INCERE

    Define the Building Envelope and Perform a Detailed Load Calc: It's ALL About Windows and Make-up Air Requirements. Know Your Equipment Capabilities

  8. #8
    Ok... IDK but the forum wont let me view that pdf you made. These are my flawed calculations (not sure how to properly add appliance loads, lighting load, occupant loads and account for infiltration and duct design) How does it look? (seems low to me... but I know contractors tend to way oversize so maybe its legit)

    System 1

    Project 53 Reservoir System 1 Totals
    ==========================================
    Cooling Load : 15,346 Btuh
    Cooling Load tons : 1.2788373777029518
    Latent Cooling Load : 2,434 Btuh
    Sensible Cooling Load : 12,912 Btuh
    Sensible Heat Ratio : 0.84
    Airflow : 734 cfm
    CFM/Ton : 573.7

    Cooling Temp Diff : 16 F
    Cooling Volume : 22,400 ft
    Floor Cooling Area : 2,800 ft
    Latent Cooling Duct Load : 0 Btuh
    Latent Cooling Infiltration Load : 734 Btuh
    Latent Cooling Ventilation Load : 0 Btuh
    Sensible Cooling Duct Load : 0 Btuh
    Sensible Infiltration Cooling Load : 704 Btuh
    Sensible Ventilation Cooling Load : 0 Btuh
    Heating Load : 43,450 Btuh
    Heating Load tons : 3.620873494514674
    Heating Temp Diff : 66 F
    Heating Volume : 22,400 ft
    Floor Heating Area : 2,800 ft
    Heating Duct Load : 0 Btuh
    Heating Infiltration Load : 7,223 Btuh
    Heating Ventilation Load : 0 Btuh

    Project Loads
    ==========================================
    Basement Wall, North, N. Basement Wall heating 8,056 Btuh, cooling 1,463 Btuh
    (2) Windows, [North], Basement Window heating 226 Btuh, cooling 78 Btuh
    (2) Windows, [North], Basement Window Copy heating 226 Btuh, cooling 78 Btuh
    Basement Wall, South, S. Basement Wall Copy heating 8,188 Btuh, cooling 1,463 Btuh
    Basement Wall, West, W. Basement Wall Copy heating 4,776 Btuh, cooling 854 Btuh
    Basement Wall, East, E. Basement Wall Copy Copy heating 3,799 Btuh, cooling 569 Btuh
    Above Grade Wall, North, N. Wall heating 1,037 Btuh, cooling 274 Btuh
    Window, [North], Sliding Door heating 1,106 Btuh, cooling 419 Btuh
    Window, [North], Window 3046 Copy heating 367 Btuh, cooling 114 Btuh
    Above Grade Wall, West, W. Wall Copy heating 640 Btuh, cooling 169 Btuh
    (2) Windows, [West], Window 3046 heating 734 Btuh, cooling 755 Btuh
    Above Grade Wall, North, N. Wall Copy heating 459 Btuh, cooling 121 Btuh
    Window, [North], Sliding Door Copy heating 1,106 Btuh, cooling 419 Btuh
    Above Grade Wall, East, E. Wall heating 557 Btuh, cooling 147 Btuh
    Above Grade Wall, East, E. Wall Copy heating 557 Btuh, cooling 147 Btuh
    Above Grade Wall, South, S. Wall heating 620 Btuh, cooling 163 Btuh
    (2) Windows, [South], Window 3056 heating 865 Btuh, cooling 483 Btuh
    Above Grade Wall, South, S. Wall Copy heating 182 Btuh, cooling 48 Btuh
    Above Grade Wall, South, S. Wall Copy heating 420 Btuh, cooling 111 Btuh
    Above Grade Wall, West, W. Wall heating 355 Btuh, cooling 94 Btuh
    Floor, Basement Floor heating 1,951 Btuh, cooling 0 Btuh
    Infiltration, heating 7,223 Btuh, cooling 1,439 Btuh
    Internal Gain, heating 0 Btuh, cooling 5,940 Btuh

    Project Load Summary
    ==========================================
    Walls : heating 29,647 Btuh, cooling 5,622 Btuh
    Glass : heating 4,629 Btuh, cooling 2,345 Btuh
    Floors : heating 1,951 Btuh, cooling 0 Btuh
    Infiltration : heating 7,223 Btuh, cooling 1,439 Btuh
    Internal Gains : heating 0 Btuh, cooling 5,940 Btuh

    Room Loads
    ==========================================
    Basement : heating 27,222 Btuh, cooling 6,905 Btuh
    Bathroom : heating 182 Btuh, cooling 48 Btuh
    Dining Room : heating 2,122 Btuh, cooling 687 Btuh
    Family Room/Kitchen : heating 3,883 Btuh, cooling 1,730 Btuh
    Laundry Room : heating 776 Btuh, cooling 204 Btuh
    Living Room : heating 2,042 Btuh, cooling 793 Btuh
    ==========================================

    System 2

    Project 53 Reservoir System 2 Totals
    ==========================================
    Cooling Load : 11,519 Btuh
    Cooling Load tons : 0.9598856154521818
    Latent Cooling Load : 1,892 Btuh
    Sensible Cooling Load : 9,627 Btuh
    Sensible Heat Ratio : 0.84
    Airflow : 547 cfm
    CFM/Ton : 569.9

    Cooling Temp Diff : 16 F
    Cooling Volume : 10,752 ft
    Floor Cooling Area : 1,344 ft
    Latent Cooling Duct Load : 179 Btuh
    Latent Cooling Infiltration Load : 513 Btuh
    Latent Cooling Ventilation Load : 0 Btuh
    Sensible Cooling Duct Load : 381 Btuh
    Sensible Infiltration Cooling Load : 492 Btuh
    Sensible Ventilation Cooling Load : 0 Btuh
    Heating Load : 14,810 Btuh
    Heating Load tons : 1.2341796052991454
    Heating Temp Diff : 66 F
    Heating Volume : 10,752 ft
    Floor Heating Area : 1,344 ft
    Heating Duct Load : 475 Btuh
    Heating Infiltration Load : 3,929 Btuh
    Heating Ventilation Load : 0 Btuh

    Project Loads
    ==========================================
    Above Grade Wall, South, S. Wall heating 552 Btuh, cooling 145 Btuh
    (2) Windows, [South], Window 3046 heating 734 Btuh, cooling 410 Btuh
    Above Grade Wall, South, E. Wall heating 495 Btuh, cooling 131 Btuh
    Above Grade Wall, South, S. Wall Copy heating 261 Btuh, cooling 69 Btuh
    Window, [South], Window 3046 Copy heating 367 Btuh, cooling 205 Btuh
    Above Grade Wall, North, N. Wall heating 500 Btuh, cooling 132 Btuh
    Window, [North], Window 2432 heating 203 Btuh, cooling 70 Btuh
    Above Grade Wall, East, E. Wall Copy heating 499 Btuh, cooling 132 Btuh
    Above Grade Wall, West, W. Wall heating 423 Btuh, cooling 112 Btuh
    Window, [West], Window 3046 Copy Copy heating 367 Btuh, cooling 419 Btuh
    Above Grade Wall, South, S. Wall Copy heating 710 Btuh, cooling 187 Btuh
    Window, [South], Window 3046 Copy heating 367 Btuh, cooling 205 Btuh
    Above Grade Wall, North, N. Wall Copy heating 423 Btuh, cooling 112 Btuh
    Window, [North], Window 3046 Copy heating 367 Btuh, cooling 127 Btuh
    Above Grade Wall, West, W. Wall Copy heating 423 Btuh, cooling 112 Btuh
    Window, [West], Window 3046 Copy heating 367 Btuh, cooling 419 Btuh
    Above Grade Wall, North, N. Wall Copy heating 209 Btuh, cooling 55 Btuh
    Window, [North], Window 2432 Copy heating 203 Btuh, cooling 70 Btuh
    Above Grade Wall, North, N. Wall Copy Copy heating 423 Btuh, cooling 112 Btuh
    Window, [North], Window 3046 Copy Copy heating 367 Btuh, cooling 127 Btuh
    Ceiling, Ceiling heating 422 Btuh, cooling 319 Btuh
    Ceiling, Ceiling Copy heating 71 Btuh, cooling 54 Btuh
    Ceiling, Ceiling Copy heating 348 Btuh, cooling 264 Btuh
    Ceiling, Ceiling Copy Copy heating 388 Btuh, cooling 294 Btuh
    Ceiling, Ceiling Copy heating 290 Btuh, cooling 220 Btuh
    Ceiling, Ceiling Copy Copy heating 145 Btuh, cooling 110 Btuh
    Ceiling, Ceiling Copy heating 290 Btuh, cooling 220 Btuh
    Ceiling, Ceiling Copy heating 192 Btuh, cooling 146 Btuh
    Infiltration, heating 3,929 Btuh, cooling 1,004 Btuh
    Internal Gain, heating 0 Btuh, cooling 4,980 Btuh
    Ductwork, heating 475 Btuh, cooling 560 Btuh

    Project Load Summary
    ==========================================
    Walls : heating 4,919 Btuh, cooling 1,297 Btuh
    Glass : heating 3,341 Btuh, cooling 2,051 Btuh
    Ceilings : heating 2,147 Btuh, cooling 1,626 Btuh
    Infiltration : heating 3,929 Btuh, cooling 1,004 Btuh
    Ducts : heating 475 Btuh, cooling 560 Btuh
    Internal Gains : heating 0 Btuh, cooling 4,980 Btuh

    Room Loads
    ==========================================
    Bathroom : heating 576 Btuh, cooling 245 Btuh
    Bedroom 2 : heating 2,330 Btuh, cooling 1,727 Btuh
    Bedroom 3 : heating 1,932 Btuh, cooling 1,489 Btuh
    Bedroom 4 : heating 1,116 Btuh, cooling 3,337 Btuh
    Master Bathroom : heating 1,602 Btuh, cooling 622 Btuh
    Master Bedroom : heating 2,275 Btuh, cooling 2,706 Btuh
    Master Bedroom Closet : heating 723 Btuh, cooling 341 Btuh
    Stairway : heating 199 Btuh, cooling 152 Btuh
    ==========================================

  9. #9
    Join Date
    Nov 2004
    Location
    SW FL
    Posts
    6,429
    Quote Originally Posted by dan_liptak View Post
    Ok... IDK but the forum wont let me view that pdf you made. How does it look?
    System 1

    Project 53 Reservoir System 1 Totals
    ==========================================
    Cooling Load : 15,346 Btuh
    Latent Cooling Load : 2,434 Btuh
    Sensible Cooling Load : 12,912 Btuh
    Cooling Temp Diff : 16 F
    Cooling Volume : 22,400 ft
    Floor Cooling Area : 2,800 ft

    Heating Load : 43,450 Btuh
    Heating Temp Diff : 66 F

    Heating Volume : 22,400 ft
    Floor Heating Area : 2,800 ft
    Heating Infiltration Load : 7,223 Btuh

    Project Load Summary
    ==========================================

    Walls : heating 29,647 Btuh, cooling 5,622 Btuh
    Glass : heating 4,629 Btuh, cooling 2,345 Btuh
    Floors : heating 1,951 Btuh, cooling 0 Btuh
    Infiltration : heating 7,223 Btuh, cooling 1,439 Btuh
    Internal Gains : heating 0 Btuh, cooling 5,940 Btuh

    Room Loads

    ==========================================

    Basement : heating 27,222 Btuh, cooling 6,905 Btuh

    ==========================================

    System 2

    Project 53 Reservoir System 2 Totals
    ==========================================
    Cooling Temp Diff : 16 F
    Cooling Volume : 10,752 ft
    Floor Cooling Area : 1,344 ft

    Heating Load : 14,810 Btuh
    Heating Temp Diff : 66 F
    Heating Volume : 10,752 ft
    Floor Heating Area : 1,344 ft


    ========================
    Walls heating load is not accurate.

    Heating Temperature difference in basement to soil is
    about 70- 45 = 25'F

    Post # 6
    My ONLY question was
    ___ What is the Winter Design Temperature?


    If you wish to see Attachment to post # 7, you'll have to e-mail me.
    Designer Dan
    It's Not Rocket Science, But It is SCIENCE with "Some Art". ___ ___ K EEP I T S IMPLE & S INCERE

    Define the Building Envelope and Perform a Detailed Load Calc: It's ALL About Windows and Make-up Air Requirements. Know Your Equipment Capabilities

  10. #10
    Join Date
    Jan 2009
    Location
    Keokuk, IA
    Posts
    5,520
    Quote Originally Posted by dan sw fl View Post
    Walls heating load is not accurate.

    Heating Temperature difference in basement to soil is
    about 70- 45 = 25'F

    Post # 6
    My ONLY question was
    ___ What is the Winter Design Temperature?


    If you wish to see Attachment to post # 7, you'll have to e-mail me.
    +1, even uninsulated and unfinished, basements do not lose very much heat, expecially if you only keep then about 62-65F most of the winter. I think that 25F number is a little conservative. There is a temrpature gradiant. Hte soil under hte floor slab is likely to be closer to 50-55F most of the winter even in your climate. Closer to the surface it's a little warmer. Especailly in NY, when snowfall usually covers the ground and insulates it. Frost level is what, 16-24", and the temp rises quickly below that.

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •  
Comfortech Show Promo Image

Related Forums

Plumbing Talks | Contractor Magazine
Forums | Electrical Construction & Maintenance (EC&M) Magazine
Comfortech365 Virtual Event