Open hardware HAVCL system - Page 1
Forum section: electronics / projects

author: jpyeron
author_rank: Regular Contributor
timestamp: February 23, 2020, 05:49:01 pm
content: Reading Dave's tweet "HELP: I'm looking for a quality ... 600mm or 1200mm LED panel ceiling lights ... 5000K-5500K and high CRI ... lots of crap out there",https://twitter.com/eevblog/status/1230984296065716224, I thought I would post a work-hobby project of mine.I has been undergoing various spurts of attention for the past 20 months.In the various offices (cubicles) I have worked in, I have been very dissatisfied with the environmental controls. Too hot, too cold, too bright, too dark, etc. A big goldilocks problem.Over the past few years, I have reached out to various HVAC and lighting companies about the solution. My research has shown that solution are divided into 2 broad categories 1) the one off solution aka, home automation, 2) the 10,000 SQFT+ office solution. In the first set of solutions, they offer no price breaks, energy efficiency, or freedom to tinker/avoid dial home apps. In the second set of solutions, price is "not an objective", SCADA controls are proprietary and individual comfort is not a concern. Lighting follows in the same pattern.Here are some of the project' requirements/goals:low unit cost @ QTY1 retail; linear price increase with SQFTOne unit per seatEach seat can set HVAC temperatureEach seat can set lighting (on/off)operation costs <= existing HVAC & Lighting (combined or seperate) annuallyTotal installation and operation pricing ~< existing HVAC & Lighting (combined or seperate) solutions over first 2 years208 - 240 mainsaddressable via IPv4/IPv6Each seat can set lighting temperatureEach seat can set lighting RGBTwo lights per seatVery low standby power consumption (commercial electric billing)Very low waste power consumption in use (commercial electric billing)Support IEEE 802.3Support IEEE 802.11Support IEEE 802.15Support Occupancy sensor and relaysSupport LEED (U.S. Green Building Council) goals. Efficiency in more than just electricity...Support time of day lightingCurrent project status:Dampers: Supply chain established. Prototypes tested. The HVAC damper control unit cost is 10$ @ 100 units. The damper controller is a servo with zero standby power usage and 12VDC motor voltage. Parts are currently machined, leaving an area for further cost reductions.CPU: Supply chain established. Prototypes tested. The CPU board is "based" on the Raspberry PI 4. It is a 12VDC supply, I/O breakout, including I2C and SPI, 802.3, 802.11, and 802.15. 25$ @ 1 unit, difficulty in negotiating price reductions for larger QTY.Lights' frames: Supply chain in negotiations, Prototypes tested. are 24"x24" or 600mmx600mm drop ceiling style. Aluminium frame, pcb bonded with thermal epoxy (2 parallel sides), polycarbonate diffuser, plastic / mylar white reflector, sheet steel backing - screwed to aluminium frame. Prototype unit cost 12$ @ QTY 2.Lights' LEDs: Temporary supply chain: digikey - QTY 100. currently selecting LED bar layout (PCB physical dimensions design vs power/heat vs light output usefulness). Two competing designs    vs      ; max 120 LEDs / PCB, 2 PCBs / light - prototype cost between 10$ and 90$ per light fixture based on LED models selectedPower supply: status = paper napkin sketches; Goals 1) modular (socketed) digitally controllable CC supply rails - allowing for different LED panel max voltage, max current; 2) high efficiency 12V rail supporting CPU (no brownout on accessory draw) and accessories; 3) I2C or similar controlChassis: supply: status = paper napkin sketches; Goals 1) fit in standard 2 gang grounded metal box; 2) have a high mains side isolated from a stackable 2 gang low voltage side.Block diagram:Thoughts?

author: jpyeron
author_rank: Regular Contributor
timestamp: February 23, 2020, 05:59:30 pm
content: On to Dave's tweet... which 5k white LED would you use?CRI 90% 5.7K 0.04020$ -https://www.digikey.com/product-detail/en/cree-inc/JE2835AWT-00-0000-000A0UF957E/JE2835AWT-00-0000-000A0UF957ECT-ND/9974563CRI 95% 5.7K 0.14830$ -https://www.digikey.com/product-detail/en/bridgelux/BXEN-57S-13H-9C-00-0-0/976-BXEN-57S-13H-9C-00-0-0CT-ND/11203661CRI 95% 5.6K 0.16910$ -https://www.digikey.com/product-detail/en/luminus-devices-inc/MP-3030-1100-56-95/1214-1348-1-ND/5731661CRI 95% 5k 0.37210$ -https://www.digikey.com/product-detail/en/seoul-semiconductor-inc/S1S0-3030509503-0000003S-00001/897-1357-1-ND/9686880or something else?

author: JKKDev
author_rank: Regular Contributor
timestamp: March 12, 2020, 06:33:06 am
content: IMO with efficiency in mind (both power- and money-wise) you should look for the best lumen/W/$ performers and pick a few test samples to varify the stated numbers. You should also quantify the production cost differences between placing X number of Y lumen/W leds vs 3X number of Y/3 lumen/W leds (eg. 50 120lm/W vs 150 40lm/W). At that point if you still have multiple contenders you can split production to best CRI light, highest efficiency light,...