Math & Numbers
Air Changes per Hour (ACH, n = Q/V)
Compute the air change rate (ACH / n) of a room from the outdoor supply airflow Q and the room volume V: n = Q/V (1/h). Three modes: solve ACH (given Q and V), solve airflow (given n and V), or solve volume (given n and Q). Flow in m³/s/m³/h/CFM, volume in m³/ft³/L. Also reports the well-mixed single-zone purge time to reach a target residual fraction ε (default 1%): t = −ln(ε)/n hours.
Quick start
Call this tool from your code in three languages.
curl -X POST 'https://api.elysiatools.com/en/api/tools/air-changes-per-hour' \
-H 'Content-Type: application/json' \
-d '{"mode":"ach","flowRate":300,"flowUnit":"m3/h","volume":60,"volumeUnit":"m3","ach":0,"purgeFraction":0.01,"decimalPlaces":4}'API reference
Send a POST request with your inputs as JSON. File parameters require a separate upload first.
Endpoint
POST https://api.elysiatools.com/en/api/tools/air-changes-per-hourParameters
| Name | Type | Required | Description |
|---|---|---|---|
| mode | select | No | Solve ACH n (needs Q and V), solve Air Flow (needs n and V), or solve Volume (needs n and Q). |
| flowRate | number | No | Outdoor / supply volumetric airflow Q. Enter in the selected Flow Unit. Required unless solving flow. |
| flowUnit | select | No | — |
| volume | number | No | Room (conditioned space) volume V. Enter in the selected Volume Unit. Required unless solving volume. |
| volumeUnit | select |
MCP integration
Add this tool to your Model Context Protocol server so AI agents can list and call it.
Server configuration
Add this block to your MCP client configuration:
{
"mcpServers": {
"elysiatools-air-changes-per-hour": {
"name": "air-changes-per-hour",
"description": "Compute the air change rate (ACH / n) of a room from the outdoor supply airflow Q and the room volume V: n = Q/V (1/h). Three modes: solve ACH (given Q and V), solve airflow (given n and V), or solve volume (given n and Q). Flow in m³/s/m³/h/CFM, volume in m³/ft³/L. Also reports the well-mixed single-zone purge time to reach a target residual fraction ε (default 1%): t = −ln(ε)/n hours.",
"baseUrl": "https://api.elysiatools.com/mcp/sse?toolId=air-changes-per-hour",
"command": "",
"args": [],
"env": {},
"isActive": true,
"type": "sse"
}
}
}List available tools
After connecting to the SSE endpoint, list the exposed tools:
{
"jsonrpc": "2.0",
"id": 1,
"method": "tools/list"
}Call this tool
Invoke the tool by its id, passing arguments built from its parameters:
{
"jsonrpc": "2.0",
"id": 2,
"method": "tools/call",
"params": {
"name": "air-changes-per-hour",
"arguments": {
"mode": "ach",
"flowRate": 300,
"flowUnit": "m3/h",
"volume": 60,
"volumeUnit": "m3",
"ach": 0,
"purgeFraction": 0.01,
"decimalPlaces": 4
}
}
}