Comp 2 BTU study

Building energy use comparisons

As part of our IoT development work, MCCI and NY Passive House have been partnering to reduce the cost of monitoring buildings (both high performance buildings and conventional construction). This low-cost study identified eight-fold differences in energy intensity across a variety of buildings. By choosing buildings at the same altitude and in the same microclimate, we are able to focus on differences in construction.

We started monitoring electricity use and temperature a few years ago, using MCCI’s Model 4811 remote power meter with LoRaWAN® technology. This meter allows us to retrofit existing buildings with high-accuracy real-time power monitoring, without requiring Wi-Fi, cellular, or wired connections. We combined that with MCCI’s Model 4822 and 4832 indoor and outdoor environmental sensor.

The data we got was pretty comprehensive for the Passive House buildings, because they only used electricity. But we wanted to compare to more conventional buildings in the same micro-climate and ecotome. For that, we needed cost-effective ways of monitoring fuel oil and propane consumption. MCCI’s engineers responded with two new products, now in test in several buildings around Ithaca, NY.

  • The MCCI Model 4861 Propane/Natural Gas meter combines an MCCI Catena® 4612 or 4801 LoRaWAN sensor with low-cost meter with pulse output.
  • The MCCI Model 4871 Fuel Oil meter combines a 4612 or 4801 with a high quality fuel oil flow meter. (Not all flow meters are alike, and we want to be sure not to damage the boilers at our study sites. There are a lot of counterfeit flow meters of unknown quality on the market. After some research, MCCI selected high quality meters from Aichi Tokei in Japan, and sourced them directly from the factory.)

We run the data through our normal server  (our open-source “Docker IoT Dashboard“, using a Node-RED / InfluxDB / Grafana pipeline). We installed in early February and were immediately getting interesting data. Installation was done by our local HVAC team, Hubbard Heating and Plumbing; MCCI provided diagrams, and Hubbard did the rest. It took between one and two hours per installation. The cost per meter was about $300 for equipment. To simplify installation, all meters use primary batteries only; part of the study is to determine battery life, but we are estimating one to two years, transmitting data every six minutes. We’re using The Things Network in Tompkins County, NY; so we didn’t have to set up a network and data charges are not a factor.

We instrumented seven sites; three Passive House certified buildings “Unit 1” through “Unit 3”, and four comparables “Comp 1” through “Comp 4”.  (We also have a “Comp 1”, but for logistical reasons we’ve not added full energy capture there yet.)

  • Unit 1 and Unit 2 are twin Passive Houses, built to the same floor plan: two-story 1,440 sq ft detached houses with solar PV systems on the roof and solar hot water.
  • Unit 3 is a two-story 1,088 sq ft Passive House, but it’s a row house, without solar PV system.
  • Comp 1 is a 2000-sq-ft two-story house with basement, built in 2002. It has forced-air central heat powered by natural gas. Hot water and cooking are also natural gas.
  • Comp 2 is a 1900-sq-ft farmhouse, built in 1847. It has a low-pressure steam heat system fired by fuel oil. Propane is used for hot water, cooking, and a clothes dryer. Windows are 30 years old.
  • Comp 3 is a 1200-sq-ft bungalow, built in 1970. It has forced-air central heat fired by propane; propane is also used for hot water, cooking and a clothes dryer. Windows are of varying age. Minimal insulation.
  • Comp 4 is a 5900 sq-ft commercial building. It is an older farmhouse with two stories plus large finished basement. It was renovated and reconstructed in 2008. It’s not insulated to Passive House standards, but is reasonably tight. It has zoned hot-water baseboards, with a boiler fired by fuel oil. Hot water also is provided by the boiler. Only limited cooking is done at the facility, and there’s no propane.

Fuel Oil Raw Data

Let’s start with the raw data. Here’s seven hours of fuel use at Comp 2:

Fuel Oil plus outdoor temperature, Comp 2

It can be pretty cold in Ithaca in February; the temperature didn’t get above freezing all day. This is all data from Feb 4, 2021.

As you can see, the control system runs the pump for about 15 minutes, pauses it for maybe 5 minutes, and then runs for another 15 minutes. Remeber, this is a low-pressure steam boiler; when the burner comes on, it has to run for a while to start driving steam into the pipes.

You can also see a repeatable pattern: the pump pushes a little more oil at the start of a burn cycle than at the end. We’re not sure why that is, fuel oil pumps are supposed to push at a constant rate. This is exactly why we wanted to see “actual fuel burn” rather than “pump-on time”.

Let’s look at “Comp 4” next. It has a baseboard hot-water system (not steam) and the operating pattern is completely different. Same time scale as above.

Comp 4 Fuel Oil Demand

Notice that the pump is only on very briefly, about a minute at a time (except occasionally). We actually are checking with the HVAC engineers, because this looks like a broken control system – we think it should not be doing this. The variation in max flow is due to the fact that our totalizing sample rate (1/minute) is very close to the on/off cycle time so there’s a little bit of aliasing. The peak flow is 4.5 L/m, as compared to around 3.2 L/m at Comp 2.

Propane Raw Data

Let’s compare propane next. Here’s the data for propane use at Comp 2:

Graph of propane use, Comp 2

Propane rate of flow depends on what’s using the propane. We happen to know that the two short-but-broad pulses at 17:00 and 21:30 are domestic hot water; the tall, narrow spike at 20:0 is cooking, and the blip at 19:00 is the water heater maintaining temperature.

Comp 3 also uses propane:

Comp 3 Propane Demand

Note that the use pattern is spikier; the peaks are a little higher. It appears that the furnace is cycling two to three times per hour; this is as it should be.

Comparing Buildings: BTU/Sq Ft.

The data is interesting, but we’re really like to compare buildings of different kinds and sizes. To do this, we have to convert the different energy inputs to a common unit — we’ll use BTU, British Thermal Units. But then, since the buildings vary a lot in size, we need to normalize; all other things being equal, a larger building will use more energy than a small one. The Passive House community normalizes based on square feet of living area. Finally, we have to compare energy use over a consistent interval; let’s use a day.

Let’s start with Comp 2, the 1847 farm house. This chart shows BTU/sq ft (the ramp), along with indoor/outdoor temperatures.

Comp 2 BTU study

This chart sums propane, electricity, and fuel oil to give us the total BTU use, as the purple staircase. The building used about 550 BTU/sq ft on the day measured.

Let’s compare to Comp 4, the offices. In comparison to the old house, the offices are about twice as efficient:

Comp 4 BTU/sq ft study

From the picture, you can see that the heat input from oil is relatively constant (unlike the farmhouse, where there’s a staircase effect as the burner cycles). You can also see that electricity is a major energy input — there’s a large server farm in the basement, and the waste heat is partially reused.

What about the 1970 bungalow?

Comp 3 BTU Study

It’s actually just about the same as the office building. This is surprising, as the office building is tighter, has more modern buildings and is better insulated. However, some of the heat from the server room is being dumped out of the building; and the control system for the boiler is probably cycling too rapidly. We plan to study this to see if we can get some savings.

Finally, to give us some perspective, here’s the energy use from a Passive House constructed in 2013. This is an all-electric building. It has no solar hot water, so the energy use shown represents the quality of construction:

Unit 3 BTU Study

Unit 3 is only using 65 BTU/sq ft for this day. This means it’s five times more efficient than either Comp 3 or Comp 4, and more than eight times more efficient than Comp 2!

Conclusions

Here’s what we conclude:

  • MCCI’s low-cost metering technology combined with LPWAN radio connections were, as expected, easy to install and trouble free. (We mention this because it still seems remarkable.)
  • Comparing buildings based on energy intensity is a great way to discover actionable discrepancies.
  • Comparing buildings based on energy intensity is a great way to demonstrate benefits of high performance construction techniques.
  • Comparing buildings based on energy intensity is a great way to motivate building owners and maintenance staff to improve building performance, because it shows what’s possible.
  • We need a cost-effective way to measure natural gas. Installing propane meters is simple; but due to regulatory issues and cosmetic issues, installing gas meters is not nearly as easy.

More Info

Information on the Model 4811 Electric Meter, the Model 4822 Indoor Environmental Sensor and the Model 4832 Outdoor Environmental Sensor can by found by following the links. The Model 4861 Propane Meter and Model 4871 Fuel Oil Meter are not yet on the website but are available by contacting us directly. Our open-source software is on GitHub.
Interested in monitoring building performance using MCCI’s NerveCircuit™ technology? Drop an email to sales@mcci.com, and we’ll set up an introductory discussion.

Updates

  • 2021-06-14 added more details about comparables, corrected a few typos.

USB-IF Compliance Testing Tips #2 – Pre-Compliance Testing

One question we are often asked is, “How long will the testing take?” The answer to this question can lead to very different consequences depending on the vendor’s schedule. If the device is expected to go on the market within the next year, then the answer is merely logistical. However, if the device is expected to go to market next week, then testing at this point is a leap of faith, simply because there is no guarantee that the device will pass. Time for debugging must be a factor in test scheduling.

No matter how well constructed, well engineered, and well thought-out a device is, there are always corner cases that can force the device to stumble. Therefore, when scheduling the compliance test, it is important to allocate some time for troubleshooting and debugging potential problems. These problems may not be the obvious ones like signal quality, basic enumeration, or inrush. The problem can be a very subtle failure: for example, the device might fail because it draws too much current on a hub with a suspended port. Or perhaps it has a back-drive failure because the D+ pull up is hardwired. Regardless of the type of failure, it is important to recognize that there may be unforeseen difficulties. Therefore, if it is feasible, testing should be scheduled around these unfortunate possibilities.

Developers should consider the benefits of testing before the ultimate factory-grade product is complete. This can be done internally or through a test lab. MCCI frequently tests devices that are not in their final state. We perform what we call half-tests on devices that may not even have OS drivers yet. While bringing such a device to an actual USB-IF Compliance Workshop may not be worth the time and effort, we strongly advise you to either send your unfinished devices to a certified test lab like MCCI or to test them internally. Ultimately, the time and money you spend on testing early in the development will save you money overall. The cost of running a half-test on a development platform with the silicon that will be in the final product is much less than the cost of re-spinning the silicon later.

Naturally, early testing might not catch everything. There can always be PCB layout changes or changes in the manufacturing BOM that cause unintended results. Last-minute problems are very frequently encountered and can never be completely eliminated. Still, more often than not, early testing and adequate planning to include enough debug time during the final test will greatly alleviate the ravages of any last minute catastrophes that do arise.

USB-IF Compliance Testing Tips #1 – Command Verifier (CV)

The process of obtaining USB-IF certification can be difficult, but not just because of the specification requirements. Often developers uncover problems not related to USB compliance during certification testing. For this reason, it can be helpful to test as early as possible, preferably well before the product is scheduled to be released. Of course, it is not always possible to test early, either because product requirements are in flux, extensive debug is necessary, or even because final hardware is not available. It occurred to us here at MCCI that it might be helpful for us to outline some tests that engineers can perform on their USB products in advance of those products entering the Compliance Lab. Using them may help flush out compliance problems during normal, pre-test development.

The tests we are recommending are tests that most consumer electronics product engineers should be able to perform with a small hardware investment and as little overall cost to their test budget as possible. After all, with the economic environment being what is, anything we can do to help companies avoid extra test costs or delayed market releases is for the best. Some of these tests we’re going to tell you about come from the USB-IF compliance test suite, while others are our original work. Regardless, it is our hope to help you achieve USB-IF compliance for your USB product.

CV

This handy tool is a bit of software that the USB-Implementers Forum (USB-IF) uses to test a device’s basic functionality. CV, or Command Verifier, tests for compliance with Chapter 9 of the USB 2.0 specification. CV is one of the most helpful tests a developer can run on their device. Run it as early as possible. It will test enumeration, the device’s descriptors, and the device’s response to a number of specific requests.

The CV test program is free and can be downloaded from the USB-IF website:

http://www.usb.org/developers/tools/

Setup is fairly straightforward. In addition to the device, all the user needs is a high-speed host controller and a high-speed hub. When CV runs it takes control of the high-speed host controller (EHCI). The high-speed hub is then plugged into the host, and the device being tested is plugged into the high-speed hub. CV enumerates the device being tested without the use of any Windows drivers. CV can be run on either Windows XP or Windows 7 systems.
CV sends various commands through the bus, analyzes the responses from the device, and logs the various results into an html file. While it does not test every aspect of the Chapter 9 requirements, a passing test assures developers that they are on the right track.

Introducing the Type-C SuperMUTT

MCCI introduced our Model 3501 Type-C SuperMUTT today, the latest addition to our line of USB development tools!

You may be wondering, however, “What’s a SuperMUTT?”

Let’s break it down.

In the beginning…

Back in the early days of USB 2.0, Microsoft needed a tool that would let them verify the operation of high-speed host controllers and of their USB host stack. So they invented a test tool, and named it the “Microsoft USB Test Tool”, or “MUTT“.  This device has a Cypress FX2 controller chip and a lot of test firmware that let it emulate a variety of devices and thoroughly exercise all four transfer types on USB: bulk, interrupt, control and isochronous. It was a small device, that plugged into the USB port like a thumb drive.

The next generation…

When USB 3.0 came out, Microsoft wanted a similar tool for testing SuperSpeed host ports. So the “SuperMUTT” was born.  This device has a Cypress FX3 controller, which adds SuperSpeed support (now known as USB 3.1 gen 1, or 5 gigabit USB).  Again, they added a lot of firmware and host software, but the concept was the same — a small devic ethat plugs into the USB port like a thumb drive.

Type-C

I suspect you can guess where this is going.  The Type-C SuperMUTT is simply the SuperMUTT, enhanced for Type-C support. But why is it so much bigger?

Well, the Type-C connector can do a lot more than the original Type-A connector.  For example:

  • You can power your PC through the port
  • You can use DisplayPort alternate mode to drive a monitor from the port
  • If your PC is running from another power source, you supply a lot of power to external devices

This is very nice for the user, but it’s a big job to test Type-C software thoroughly.  So the Type-C SuperMUTT adds the following features to the original SuperMUTT

  • Support for signaling over the CC wire of the Type-C cable
  • Support for the USB Power Delivery specification
  • Ability to pass power from an external supply to the unit under test (as instructed by the Power Delivery specification)
  • Support for alternate modes, particularly DisplayPort
  • Support for connecting to an external charger, again for testing.

In order to be able to accurately emulate all the variants of the PD specification, the PD interface is implemented with a Lattice iCE 40 UltraPlus FPGA. This gives the ability to emulate the different design decisions of different manufacturers, as well as the ability to emulate and inject various kinds of faults.

With all of this functionality, and all of the electrical power that can be handled, we needed to have a fan. And we needed to have a robust enclosure.

Hence the model 3501 as you see it above.

As you might guess, the 3501 was developed in conjunction with Microsoft; they’ll be supplying the Windows test software and embedded firmware for the product. We’ll be receiving the second production lot in late September, and we’re taking orders now via our online store.

A slight digression

You might have noticed that some of our literature calls the Model 3101-family of USB Connection Exercisers the “MUTT ConnEx-C”. This is because it’s really a part of the Microsoft USB Test Tool family (and you can see it here on the MUTT page at Microsoft).

Conclusion

Interested in learning more about the details? Post a comment here with your questions, or tweet me at @TmmMCCI, and I’ll do my best to answer.

RealVNC selects MCCI as Automotive Partner

TOKYO, JAPAN, November 11, 2013 – RealVNC Limited, the original developer and leading provider of VNC® remote access and control software, and MCCI Corporation, the inventor of the industry standard USB NCM protocol for high-speed networking over USB,  today announced that RealVNC has selected MCCI as their preferred supplier of NCM class drivers for use with RealVNC’s VNC® Automotive products.

VNC Automotive is a collection of software modules that allow automotive head units and other consumer electronic products to incorporate comprehensive remote access and remote control capabilities for integrating smart phones with in-vehicle information and entertainment systems.

“Users are able to access their mobile content, such as navigation applications, traffic updates, music libraries and internet radio stations from the vehicle’s main display unit,” said Tom Blackie, VP Mobile at RealVNC. “The mobile device can be directly accessed and controlled from the vehicle’s head unit touch screen, bezel keys, steering wheel switches and by voice command, ensuring content can be accessed safely and simply. VNC Automotive gives OEMs a single common solution with access to the widest coverage of mobile devices, including many existing legacy devices already in use with end users.”

VNC Automotive is commonly used to connect smart phones to cars using USB. According to Terry Moore, CEO of MCCI, “USB provides an inexpensive, secure and high-throughput data connection, and can charge the phone while the user is accessing their mobile content. However, USB implementation is not as simple as it seems, and the user’s experience is frequently limited by the quality of the underlying USB implementation.”

Advanced phone/car connectivity is built using existing industry standards. MirrorLink™ (from the Car Connectivity Consortium) uses the VNC protocol and NCM over USB to integrate the phone with the car.  Apple’s iPod OUT performs similar functions in a way that is optimized for Apple’s products.

NCM is the unifying technology that allows modern protocols to run over USB without tailoring the protocols specifically for USB. NCM bridges between Ethernet-style datagram traffic and native USB. It is optimized for moving IP traffic between embedded systems at very high speeds. “We have found that MCCI’s implementations of NCM are consistently of the highest quality, and deliver the highest throughput for the user’s mobile content,” said Blackie. “As the key contributors and editors of the NCM specification, they know how to translate the requirements of the specification into fast, effective implementations. Our customers typically see a 5x increase in overall system throughput, especially for video content. Their years of experience supporting phone and platform OEMs in Japan, Korea, and Europe translate directly into higher quality code, more stable implementations, and better support for our VNC Automotive customers. Their cross-platform development strategy aligns very closely with the platforms we support.”

“Like RealVNC, MCCI specializes in delivering OEM software,” noted Moore. “MCCI supports all the same operating systems and target CPU architectures supported by RealVNC. We both support Linux, Android, Windows (XP, Automotive, CE), QNX, µITRON, and T-Kernel; running on ARM, x86, MIPS, and SH architectures from a variety of SoC vendors.”

“Automotive electronics makers often underestimate the complexity of providing a consumer-grade solution,” said Blackie. “They may try to do the higher level protocols themselves at first, but soon discover that VNC Automotive is easier and allows them to get to market more quickly. The critical nature of the USB connection is also often overlooked. The NCM specification is only 36 pages long, so appears deceptively easy to implement. We’ve had many customers come close to failing, based solely on the poor quality of the USB connection. Now, because of this partnership, they can easily get access to an integrated, pre-tested solution that meets international market needs, and interoperates with the widest possible range of smart phones.”

About RealVNC

RealVNC’s software is used by many hundreds of millions of people worldwide in every sector of industry, government and education. VNC is the original remote access software with a wide range of applications. The technology supports an unrivalled mix of desktop and mobile platforms and can be embedded in third-party products with a commercial license. www.realvnc.com

VNC is a registered trademark of RealVNC Ltd. in the U.S. and in other countries.

MirrorLink Certified™, the Design Only™ Certification Logo, MirrorLink™ and the MirrorLink™ Logo are certification marks and trademarks of the Car Connectivity Consortium LLC. Unauthorized use is strictly prohibited.

About MCCI

MCCI is a leading developer of embedded USB software for the high-volume personal computer and portable device markets. Customers include some of the world’s biggest brands in telecom, wireless, embedded and consumer devices including Qualcomm, Intel, Apple and Sony. Nearly one billion products have been delivered with MCCI technology. MCCI experts are actively involved in worldwide Technical Standards activities. A privately held corporation, MCCI has its headquarters in Ithaca, NY, with additional offices in New York City, India, Korea, Japan, and Taiwan. Visit MCCI at mcci.com, Facebook and Twitter.

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Note to Editors: MCCI, USB DataPump, and TrueTask are registered trademarks of MCCI Corporation. Other names mentioned are owned by their respective holders.