When we think about codes, it’s easy to say they are here to: • Protect safety and health of the public • Provide minimum construction standards Why is there an Energy Code? To control the amount of energy that constructed buildings consume. According to the DOE, Commercial Bldg Energy Consumption Survey • Let’s admit that most decisions made during construction are based on price and aesthetics – EE is not often a driving factor. I’d much rather have that Italian marble tile in the lobby of my building, or granite countertops in my home than a 15 SEER heat pump. How sexy is a heat pump water heater, or variable pumping? According to DOE and countless other studies, the largest end use consumer of energy in buildings: space heating, lighting, space cooling Recent research by PNNL shows that if the 2006 code were upgraded by 30 – 50%, adopted and enforced, the benefits in terms of energy 2
• Reduce energy consumption • Reduce CO2 emissions by 3% • By taking these actions, as a whole the overall cost to consumers will decrease and savings increase 2
While we will focus on the mechanical PORTION of Chapter 5, let’s stop briefly in a couple of chapters along the way 3
The Administrative Chapter contains the provisions for application, enforcement and administration of the code.
What are some of the key changes? 101.4 APPLICABILITY When different sections of the code specify different materials, methods of construction, or conflict with each other… the most restrictive governs This is good. Why? Given a choice – the least cost option will likely be the least restrictive No bullet 101.4.4 CHANGE IN OCCUPANCY 2006 stated a BUILDING changed occupancy that resulted in increased energy use = meet current code. Changed on word – but it’s important SPACES 101.4.5 New section: CHANGE IN SPACE CONDITIONING Non-conditioned space changed to conditioned space MUST meet code 101.4.6 MIXED OCCUPANCY Recognize and address mixed use buildings. Are to have two compliance submittals • Residential occupancy under residential code • Commercial occupancy under commercial code There are numerous other changes in Chapter 1. We are going to skip ahead so we can invest more time in Chapter 5. 5
What is SC Zone? 3 – 3A to be specific - We will revisit this in a few slides Now mark counties that are in the Warm-Humid category with an asterick. 6
Although this is a residential chapter, there is a change that impacts commercial systems. If you’ll look at page 32 (I believe) - Section 403.7 Systems serving multiple dwelling units shall comply with Sections 503/4 versus Chapter 4.
The 2006 Energy Code allowed sections of the buildings to comply with the code on an individual basis. For example, I may have been working with an Architect where the building owner wanted a lot of glass on the building. As long as the architect complied with ASHRAE Std 90.1-which was 2004, the building envelope passed. On the other hand, the electrical and mechanical systems designs could follow the prescriptive path of the code – Chapter 5 – and be in compliance. Under the 2009 code, buildings must either comply with Chapter 5 in its entirety or ASHRAE Std. 90.1. Compliance approaches can no longer be mixed. Also the ASHRAE Standard 90.1 is based on 2007
You may be thinking OK Tracy, WHAT ARE THE COMPLIANCE OPTIONS NOW? 1. Prescriptive has less flexibility, but can be more straightforward to comply with • < 40% of gross wall area as vertical fenestration • < 3% of gross roof area as skylights 2. For a design that does not fit within the tables there is Section 506. If the energy use of the overall building is less than the “base” building, the building complies. 9
3. ASHRAE – in its entirety 9
If you do any searching on the internet, you may run across a diagram similar to this one depicting compliance options. This chart is incomplete for those of us that are visually challenged 10
I have been told many times over the years that my brain doesn’t work like the average person’s. I agree wholeheartedly with that statement. The diagram slightly modified makes more sense to me. Beneath this Document Compliance step are plan review, Inspections, and final approval steps 11
NEW SECTION – not in 2006 Since Section 502 deals with Building Envelope requirements, it seems logical to address Air leakage under the Building Envelope. 502.4 is MANDATORY It is here we find information concerning hot gas bypass. Exception Unitary packaged systems with cooling capacities less than or equal to 90,000 BTUh 12
From here we move to section 503. 12
13
Mandatory: these are requirements that must be met in every building design no matter which compliance path is chosen 14
• HVAC Load Calculations: all DESIGN LOADS shall be based on ASHRAE /ACCA standard 183 • Equipment and System Sizing: no change, size to meet the loads and not exceed • HVAC minimum equipment performance (efficiency) requirements: outlined in Tables 503.2.3 (1-7) • HVAC Systems Controls: new provisions for snow melting systems • Ventilation • Energy Recovery 15
One of my personal favorite topics. Why? More than 20 years ago, the utility company I worked for asked me to get my ACCA certification and teach residential load calculations to contractors involved in our programs. I understood what happened in the field – now I needed to understand the science behind load calculations. Mastered residential, then moved to commercial calculations, duct design, and equipment sizing. As I worked with contractors, I noticed a trend in the trade – companies had trouble with load calculations, equipment sizing, and duct design Whether it was a small start up or an established residential company - when they transitioned to light commercial a higher number of problems started to occur. Contractors would bring me samples of the loads they had run for this facility or that – and they were on Manual J forms! 16
Inside the cover, a few pages in there was a page titled HOW TO USE THIS MANUAL. It contained the following paragraph: This manual should not be used to estimate heating and cooling loads for commercial, industrial or institutional structures. 17
Answer: #c 18
Answer: #a 19
Highlight a couple of changes from 2006, and pose a few questions. The following 2 slides are expanded portions of this table 20
• What is the minimum efficiency for a 18,000 BTUh single packaged unitary AC? 13 21
Bard, Marvair systems, 3 to 5 tons 22
I have added red text behind the title. What’s the clue to this applying to heat pumps? HSPF 23
Just as with A/C equipment, the SEER ratings have been increased for systems < 65,000 BTUh • 2006 levels shown as ‘before’ values 24
• 2006 values shown as “BEFORE” 25
Continuation of the table, showing the equipment heating performance efficiency requirements. PTAC tables 503.2.3(3) still in IECC, no change. No change to Warm Air furnaces (gas or oil) table 26
Slight modification to Boiler table. Changed the symbol for Combustion efficiency – used to be Ec. Now Ee. The table previously contained the thermal efficiency value, with notes. The combustion efficiency has been added as a min cap – not new, was buried in the footnotes previously. No other change. 27
Numerous changes to the Water Chilling Packages table • Water cooled centrifugal water chilling packages: alternate efficiency adjustments allowed (formulas) 28
Not required in 2006 IECC Demand control ventilation (DCV) : a ventilation system that monitors and correlates the volume of outside (fresh) air to the actual occupant load by monitoring Carbon Dioxide levels. Huge in the Energy Saving arena. As a designer, we are required to ventilate per <next slide> 29
ASHRAE provides us with the guideline for Outdoor – fresh – Ventilation Air, based on ASHRAE Standard 62-2010 Since humans produce CO2 as a by product of breathing, it can’t be ignored. The higher the degree of activity, the more we produce. Ventilation rate set so that 1000 ppm CO2 is not exceeded. 30
I believe in R&D – rob and duplicate 3 air streams mixing: as a result, the sensor downstream is not accurately representing what is going on in the individual spaces. 31
Proper measurement of Carbon Dioxide levels, and can now provide dilution to the space. 32
• Systems with energy recovery per 503.2.6 • Multiple zone systems without direct digital control of single zones communicating with central control panel • Systems with design outdoor airflow < 1,200 cfm • Spaces where supply airflow rate minus any makeup or outgoing transfer air requirement < 1,200 cfm 33
No other changes 34
Added exception for factory installed piping within room fan coils and unit ventilators tested in accordance with AHRI 35
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