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Retrofits and New Controls: Sorting Out Some Options

Retrofits and New Controls: Sorting Out Some Options. Bob Davis, Ecotope. Affordable Comfort 2011 SFO. Topics. Retrofit overview Some comments on “high efficiency” equipment Newer control features. Retrofits: what are you trying to accomplish?. Consider what the “technical fix” gets you

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Retrofits and New Controls: Sorting Out Some Options

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  1. Retrofits and New Controls: Sorting Out Some Options Bob Davis, Ecotope Affordable Comfort 2011 SFO

  2. Topics • Retrofit overview • Some comments on “high efficiency” equipment • Newer control features

  3. Retrofits: what are you trying to accomplish? • Consider what the “technical fix” gets you • Spending $2000 on wall insulation will do a lot more than spending 2000 to get from a 8.2 to 9.5 HSPF heat pump • In most of US, spending the $2000 to get a 21 SEER AC or heat pump is even more of a waste of money • Consider optimizing your existing heating/cooling system

  4. Box Rating Vs Reality • Without commissioning, the capacity and efficiency of the box is a mystery ? ? ? ?

  5. Impact of Ducts - Seattle

  6. Duct retro is not just sealing • Spend $700-1000 for the sealing • Spend another 1000-1500 to add another return so that the system can breathe properly

  7. Filtration Systems • Primary purpose of system filter is to protect equipment • Salesman suggest filters keep your house clean, clear up your asthma, and improve communication with your teenagers • If you want to keep your house clean, you must (to quote Don Fugler), “do the mommy stuff”

  8. Pressure Drop Across Filters

  9. Air Handler Nameplate

  10. What About Doing Away With Ducts? • Ductless heat pumps appear to be a winner • Work best as supplements/offsets to existing systems • Whole house systems are costly

  11. 12RLS Performance Field measured COP compared to laboratory and Fujitsu data.

  12. What About Controls?

  13. Why are You Replacing the Thermostat? • Think it will save energy…. Maybe • Think it will make you cool… • Want to try a new salad dressing

  14. What has gotten better? • Cost… newer stats have largely eliminated subbases so confusion (for the installer) and cost also reduced • Controls engineers have configured stats so set up is less stressful and stats can easily by made into 24 hr devices if desired • “Enlarged print” stats are now the norm…

  15. Old Way

  16. New Way – IAQ Version Three wires

  17. Do programmable stats save energy? • It depends…. • Daily schedule (if you’re home all day, what purpose does a programmable stat serve?) • Dueling managers • Comfort vs efficiency (guess which one usually wins) • Frustration of “automatic” control

  18. Paradox of Control • The more complex the thermostat becomes, the more it can do but the less control you have over it • Frustration with “advanced” features leads to manual override

  19. What’s the Most Effective Control? US US

  20. Thermostat Subtleties • The stat may sense not just air temp but also wall temp; this can be frustrating for homeowners • “ we control comfort, not air temperature” • Most thermostats allow some “anticipation” which should increase efficiency and comfort • Older stats allowed explicit calibration (but temperature would still “droop” after many cycles) • Newer ones usually substitute cycling rate for actual anticipation

  21. More subtleties • Multistage stats call for heating/cooling in ramped amounts to (in plan) better match system output to load (“interstage differential”) • “Adaptive recovery” – early start with various ramp-up schemes… • Adaptive recovery doesn’t go well with some staged systems– failure to actually meet setpoint

  22. Setback/Setup • A modest setback (3F) in a moderate heating climate will save energy if the house is relatively well insulated and the system is sized properly • Setbacks don’t save much energy (or can even increase energy usage) if • They are used in houses with large UAs, especially in aggressive heating climates • They are used with heat pumps (ODT or no ODT) • Setup (cooling) – generally saves energy and is consistent with how most people in the US use their thermostats in cooling mode (that is, like an ON/OFF switch). Setup should also help reduce peak usage.

  23. Set-Up Impact

  24. Capacity Impact

  25. Three wires

  26. Installer Setup- VisionPro 8000 Series ENTER INSTALLER SETUP 1. Press the SYSTEM key 2. PRESS and HOLD the two unmarked keys as shown until the display changes approximately 5 seconds

  27. Installer Setup - VisionPro 8000 Step 0170 establishes type of system and number of stages (Option 7 is two heat/1 cool heat pump; Option 12 is 3 heat/2 cool heat pump) Step 0340 specifies there is an outdoor sensor; Option 2 must be selected to make the sensor an active control of strip heat. (Option 1 causes display of outdoor temperature but not active control of strip heat.) Step 0360: strip heat lockout temperature (40° F) Pro 8000 only goes to 40º F; IAQ goes lower

  28. (optional) Only wires needed

  29. Follow instructions on the inside cover of the Equipment Interface Module. Provides Wireless Setup instructions for the: Wireless FocusPRO Thermostat Portable Comfort Control Wireless Outdoor Sensor Connecting the Wireless FocusPRO 6000 31

  30. Carrier EDGE Thermostat

  31. EDGE Thermostat (Carrier) • Press FAN button for 10 seconds to enter Configuration Mode • The option number is displayed in the heat setpoint location and the configuration setting is displayed in the cool setpoint location. • On the TP--PAC/PHP (programmable) models, a box will surround the option number. • The Mode button is used to move the box between the two displayed values. • Go to Option 8 to set element lockout temperature. Lockout goes down to 5 F.

  32. Communicating Thermostats Pair up with communicating coils (“self-identification”) User inputs still needed (especially for things like strip heat and compressor lockout) Sometimes there is a “failure to communicate” so make sure stat is compatible with rest of system

  33. Carrier Communicating Stats(Infinity and Evolution) To enter INSTALL/SETUP menu, press ADVANCED button for 10 seconds Follow menu prompts to either INSTALL equipment (generally used when first powering up system) or change system settings (SETUP) When in SETUP mode for a heat pump, strip heat lockout temperature can be specified in the ELECT HEAT LOCKOUT step.

  34. Checking temperature reading at the thermostat Should be within 5 percent (1-2º F) of actual outdoor temperature

  35. Could improve comfort But… spend some time calculating loads And…try to make zones as equal in size (airflow requirement) as possible Initial checkout and periodic review are essential for fine control Does zoning save energy? Zoning

  36. HZ432

  37. HZ432 • Compatible with Variable Speed Blowers • Reduces blower speed when 1 zone is calling • Or when 25% or fewer zones are calling when more than 4 zones are controlled • Dual Fuel • Changeover by OT temperature • Or by OT Temperature and Call for 2nd stage heat • Multi-Stage OT Lockout • Connect a OT sensor to panel • When outdoor temp rises above set temp (10°-50°F)… • 2nd and 3rd stage heat is locked out on non-dual fuel systems

  38. HZ432 Other Features • Autochangeover Delay • Can be set to 15, 20, or 30 minutes • Purge Configuration • The purge time can be configured to be 2, 3.5, or 5 minutes • Multi Stage Control • The panel can control multi-stage conventional heat pump and conventional equipment by: • A multi-stage thermostat • Percentage of zones calling • Timer

  39. Dashboard Products

  40. “Smart” thermostats • Controls heating/cooling system, and… • Produces data streams (time of use, temperatures (if so equipped)) • Many are Web-accessible • Some systems offer interactive control (essentially a low-end home automation system) • Some systems email you alerts (freezing house etc) • Do they save energy?

  41. Example Report During this period the Desired Cool has been set forward 2F as this tends to be the cooler part of the day. This is a period of energy savings and will bring on the compressor if the Indoor Temp exceeds the Desired Cool set-point or if Pre-Cooling is enabled. • When tracking Relative Humidity% (RH) you can see the RH dropping after each compressor cycle and then rising again between each compressor cycle. • During the Set-Forward periods you can see the RH tracking on a steady curve relative to the Indoor Temp. During the warmer period of the day, the Desired Cool is set for 80F. During these periods the compressor will cycle for a longer duration with shorter breaks between each cycle. Each cycle time and break between cycles will vary in length due to the outdoor temperature continually changing. You will notice on Aug 4th the Outdoor Temp is cooler, therefore the compressor cycle times are shorter in duration.

  42. Ductless Heat Pump Control • Another remote • Somewhat inscrutable icons • Most folks use AUTO • Watch out for heating/cooling same day

  43. Conclusions • Beware tech fix; eat your green vegetables first • Beware of complicated controls– consider your daily pattern • Be open to new ideas but proceed cautiously

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