User manual

FAQ for CBECC-Res 2013

12. Does the compiler support multi-core processor cores or hyper-threading?

“CBECC-Res” includes two relevant components for this run-time discussion. CBECC-Res is the user

interface and compliance rules processing component, and CSE (California Simulation Engine) is the

building energy analysis component.

The compiler used to produce the CBECC-Res & CSE executables DOES support multi-core

processors and hyper-threading, but the source code (prior to release of upcoming version 3) was

not structured to support multi-threaded analysis.

In version 3, the analysis and simulation source code are not restructured to allow for multi-

threaded execution at a low level, but the analysis DOES now perform the two annual (proposed &

standard design) simulations in separate threads at the same time, enabling simulations to be

performed approximately twice as fast (unless the user's computer does not contain a multi-core

processor or support hyper-threading).

Regarding analysis run times, it would be unusual for an analysis run to take 3 to 4 minutes, even for

complex models on underpowered computers. That said, we do not regularly test unduly complex

models on underpowered computers, so we cannot provide expected performance in these

situations.

Also in version 3, if the analysis involves multiple orientations then five CSE simulations would be

performed in parallel. If five CPUs are available, then the speedup would be approximately a factor

of five. The parallel simulation change introduced in version 3 uses multiple threads in CBECC-Res to

monitor and report progress from each CSE run, and each CSE run is performed using a separate

process. CSE itself has not been modified to use multiple threads.

Another variable is Internet connection/bandwidth. The generation of compliance reports (which is

only required once a project is fairly complete), either PDF alone or 'Full' (XML w/ embedded PDF)

involves transmission of the model inputs and results to the web-based report generator and

receiving the files back from the report generator. In our experience this typically takes 10 to 20

seconds but we have seen unusual situations where bandwidth or report generator traffic or

detailed logging resulted in this step taking 1 to 1.5 minutes.

The most complex CBECC-Res single-family sample run is 2story2zoneExample#Crawl. The following

are processing times (including PDF report generation) for this model executed on a relatively

powerful laptop (Core-i7 (quad) 2.4 GHz, 8GB RAM, Win7-Pro, ~2-year old system):

In version 2 (595) the analysis took 1:50 —and in (testing) version 3 (626) the same run took 1:02 to

process.

FAQS POSTED ON JULY 17, 2014

1. I used one of the sample files for an Existing + Addition + Alteration and the CF1R conditioned

areas are off. Do you know why?

Unfortunately, the zone status for both the existing and new zones was set to “New.” Check the

zone status (across from the name on the Zone Data tab) and make sure it is set to “Existing” for the

existing building zone. (NOTE: the zone is never “altered.” Only the individual components and

surfaces of the existing building can be any of the three options.)

2. Can you explain how to use the status fields for HVAC and DHW correctly?